What is best to buy RIGHT NOW? 1150 or 1151 ?

Every new generation comes with a few flubs.... these are worked out for the most part in the 1st few months of release and applies to both CPUs and MoBos. These fixes are called "steppings":

https://en.wikipedia.org/wiki/Stepping_level

The term stepping level or revision level in the context of CPU architecture or integrated circuit is a version number.

Stepping level refers to the introduction or revision of the lithographic photomask or masks within the set of plates that generate the pattern that produces an integrated circuit. The term originated from the name of the equipment ("steppers") that exposes the photoresist to light.[1][2] Integrated circuits have two primary classes of mask sets, base layers that are used to build the structures that make up the logic such as transistors, and metal layers that connect the logic together.

Typically, when an integrated circuit manufacturer such as Intel or AMD invests money to do a stepping (i.e. a revision to the masks), they have found bugs in the logic, have made improvements to the design that allow for faster processing, have found a way to increase yield or improve the "bin splits" (i.e. create faster transistors and hence faster CPUs), improve maneuverability to more easily identify marginal circuits, or reduce test time which can reduce the cost of testing the part.

Many integrated circuits have a means of interrogating them in order to discover their stepping level. For example, on x86 CPUs executing the CPUID with the EAX register set to '1' will place values in other registers that show the CPU's stepping level.

Stepping identifiers are commonly an alphabetic letter followed by a numeric number, for example "B2". Usually, the letter indicates the revision level of a chip's base layers and the number indicates the revision level of the metal layers. A change in the letter indicates a change to the base layer mask revision and metal layers, while a change in the number indicates a metal layer–only mask revision. An analogy is the major/minor revision numbers used in software versioning. Base layer revision changes are time consuming and more expensive for the manufacturer, but some fixes are difficult or impossible to accomplish with metal-only changes to the integrated circuit.

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http://www.techpowerup.com/articles/overclocking/29

No processor design is perfect. The first version of a new microprocessor product is the A-0 step. Later, as improvements are made to the product for functional (bug) fixes or manufacturing improvements, the stepping number will increase.

Generally speaking, minor changes result in an increased number, (that is, A-1 to A-2) while more complex changes result in the letter being changed (that is, A-2 to B-0).

If new steppings come out with fewer bugs you are usually not eligible to RMA for a newer processor. Most of these bugs are supposed to be worked around in the motherboard design, BIOS (drivers), and applications.

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I generally recommend waiting a few months after each new generation's release so that:

1. The later steppings are shipped and the older ones have been sold and no longer "on the shelves"
2. We get to see who the winners and losers are by reading what MoBos are outperforming others. And yes, performance differences in gaming can be very significant. Z97 had a wide range oif performance variation with $125 boards outperforming $300 boards. With Z170, haven't seen a lot of that but haven't seen a lot of reviews either.
3. By reading user reviews from board owners at sites like newegg, we can learn which models are doing well and which ones have made their owners unhappy.

We are recommending that if you want to build a Z170 based build you wait another month and then pounce on Black Friday. BTW, the you will new generation boards out there that still support DDR3. Moderate performance DDR4 has slipped in price but the higher performance sets still demand a bigger premium than their DDR3 counterparts do.

I did expect that we'd see more head to head MoBo reviews but for whatever reason they just have not materialized. This is why I generally like to wait till this info (from overclock3d) is available. The highest performance 9sum of fps in game test suite) is assigned 100% and the rest is relative to how it stacks up against the leader

MSI Z97 Gaming 9 - 100.00%
MSI Z97 Gaming 5 - 99.86%
MSI Z97A Gaming 6 - 98.96%
Asus Z97 TUF Sabranco - 96.13%
Gigabyte Z97X Gaming 5 - 95.00%
Gigabyte Z97X SOC Force - 94.95%
Asus Z97 Maximus VII Hero - 93.67%
Asus Z97 Maximus VII Formula - 93.58%
Asus Z97 Maximus VII Gene - 91.69%
Asus Z97-A - 89.57%
MSI Z97 Mpower MAX AC - 88.20%
MSI Z97S Krait SLI - 71.01%

Again, there is wide variance in how owners feel about their purchases; a very high number of users being unhappy with their boards is a good reason to look elsewhere. The % listed are the percent of board owners who posted highly negative (1 egg) user reviews.

Asus Z97 TUF Sabranco - 3%
MSI Z97 Mpower MAX AC - 4%
MSI Z97 Gaming 5 - 10%
Asus Z97 Maximus VII Gene - 11%
MSI Z97A Gaming 6 - 12%
Gigabyte Z97X Gaming 5 - 14%
MSI Z97S Krait SLI 19%
Asus Z97 Maximus VII Hero - 19%
Asus Z97 Maximus VII Formula - 26%
Asus Z97-A - 27%
MSI Z97 Gaming 9 - 28%
Gigabyte Z97X SOC Force - 29%

Asus was the King of the Hill for a decade (2002 - 2012) but for whatever reason, from Z77 - Z97 and with the GTX 7xx thu 9xx they slipped. MSI has come on string in that timeframe but, like most everyone else, they have had some winners and some big losers. A good number of frustrations come from uneducated users.

The one from Todd here is a classic of an uneducated user blaming a company for his lack of preparation and research.

http://www.newegg.com/Product/Product.aspx?Item=N82E16813130870 (Reviews Tab)

But it is reasonable to assume that each model will attract the same % of users so the information is still valuable. Why does one model do great and one model do bad whether in performance or user ratings ? One thing is that new models tend to have more issues than upgrades. And yet, the number of highly negative user reviews for Asus boards spiked up drastically between Z87 and Z97. Looking above both Asus and MSi had great reviews and horrrendous reviews (Z-97A / Gaming 9).

I did find Asus' poor performance with Z97 to be a shocker.... and MSI kicked arse with some models and bombed on other models. Like PSUs or just about anything else, making component selection based upon whose logo is on a product is a fool's errand.

I always recommend that users do their research and forget "brand loyalty". In essence, become a "Hardware Whore" and tie yourself with whomever has the biggest numbers (performance and user satisfaction). In the era of the GTX 5xx and 6xx series, we were a 95% Asus (MoBos/ GPUs) shop .... w/ Z97 it was mostly MSI, then Gigabyte.

However, been seeing a bit of return to form for Asus.... the 9xx series overall wasn't impressive but the 980 Ti was and , so far, the Z170 MoBos are looking pretty good

I'm not seeing 60% ... at least that you can buy. Newegg lists (70) Z170 MoBos

Asus = 20 or about 28%
ASRock = 16
Gigglebyte = 15
MSI = 14
EVGA = 3
SM = 2

It's still too hard to say and I have been telling everyone if you must have it now, do Z97. looking for recent tests, I was real anxious to see what the gorgeous MSI Z170 Titanium would deliver and its a mixed bag.

http://www.overclock3d.net/reviews/cpu_mainboard/msi_z170_xpower_titanium_review/11

Just from a quick glance, it seems to have an edge on the 4 Unigine Benchmarks but is in turn edged in the gaming benchies. Unlike the above example, we are not seeing the 7, 12 and 30% differences, they are less than 1%

Unigine Benchies
MSI Z170A XPower Itanium - 100.00%
Asus Z170-A - 99.35%
Asus Maximus VIII Gene - 99.44%
Asus Maximus VIII Hero - 99.35%

Gaming Benchies (Tomb Raider, Sleeping Dogs, Hitman Absol.)
Asus Maximus VIII Gene - 100.00%
Asus Maximus VIII Hero - 98.87%
Asus Z170-A - 98.74%
MSI Z170A XPower Itanium - 97.83%

On the gaming, we are looking at just over 2% difference between 1st and last whereas before, we were talking 7% or more for most boards. In Uningine numbers, we are talking less than 1%. Before (Z97) the synthetic benchies resulted in similar placements .... here they reverse. So it's a bit harder to come to conclusions because:

a) Smaller number of boards in sample
b) Differences are very small, perhaps within test margin of error or normal variation between pieces of silicon
c) The two tests come to different conclusions

I should note that in past years or better said past generations, the results we more typical to what we see on the Z170s. I think it wasn't so much with Z97's that MSI hit a home run with the MSI Z97 Gaming 9, Gaming 5 and Gaming 6 but that Asus dropped a couple of turds with the Hero, Formula, Gene and Z97-A

I had similar experiences with Asus of late ....after shipping back a WS board Halloween, did not receive a working board till well into January. The 1st one they shipped as shaped like a banana, reminded me of some older Asrock boards I had seen years back. The I/O panel missed fitting in the case opening by 3/4 of an inch. The interesting part was ... Asus spun off Asrock so they could compete in the low budget / builder market and here all the communications I rec'd regarding "Where the hell is my board for 3 months ?" came from Pegatron, Asrock's parent company. I had numerous issues with Z87 Formula and Hero boards, well not so much multiple issues but same issues on multiple boards. The external drives not waking from sleep was solved by a new stepping but the promised BIOS upgrade for the BIOS clock freeze bug never materialized.

Still, I am by no means shy about considering an Asus Z170 board if the web site reviews, newegg user reviews and other resources show favorable results. I have seen nothing yet either way however indicating if the TS / RMA process has improved. Seems everyone out there is trying for a last place finish here.

I just might buy an XPower Titanium to leave on my desk and stare at it .... I hope other MoBo vendors follow suite with the coating process ... as well as RAM, GFX cards also

http://www.overclock3d.net/reviews/cpu_mainboard/msi_z170_xpower_titanium_review/2

Here it is then. In photographs we admit it looks like someone took a can of silver spray and went to town. In the flesh though it is, if you like that sort of thing, gorgeous. We often mention how photographs don't do justice to the looks of something when it is in front of you and the Titanium stretches this point to near breaking point. The benefits of having an all-silver board are obvious when you put a graphics card into it. Because it's so neutral it works beautifully with any colour at all.

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Another things I'd like to see more widely incorporated are:

"Steel Armor" - the PCI slots are reinforced to prevent GFX card weigt from yanking them off the board ... just had a user bring his back as his PC, well his MoBo, didn't survive a 10 mile move on the back seat of his car ... yes he used a seat belt .... but I guess a pot hole bounce did him in.

"OC Tools" - the separate board is a great idea and the dial, at least from the various reviews I have read, looks like the 1st OC tool that I'd let users walk out the door with and tell them to OC at home.

However, in it's current configuration, manually overclocking the board has proven diffucult to some.... not so much the board's capabilities as the power circuitry is outstanding, but the BIOSs load line calibration table has been reported as a bit off. Luckily this can easily be fixed with a BIOS upgrade which, again, is a reason to hold off on Z170. I expect some are better than others here (Asus has always done well here) but at this a point in time, it's just going to get better with later steppings and newer BIOSs across all vendor offerings.

Note however that many Z97 boards are already disappearing. If ya gonna go that way, no reason to hold off and soon the more popular models may no longer be available. From thanksgiving to XMas, there'll be a time when it's a tossup between Z97 and Z170. After Xmas, Z97 will be stuck with the "last generation" moniker and have greatly reduced perceived value.