Skylake LGA1151 ASUS Z170-P with i3-6100 (3.7GHz)

I have read, and since scratched off i3-6300, the extra $55 Canadian "Ain't worth it"
I have been seriously thinking about buying a refurb unit with i5-4570 Haswell gen.
But pricing out a Skylake will come out cheaper. About $135 (Canadian) cheaper, if I had a case and retail o/s.

Questions:
What brands of Mobo's are the best? Is it ASUS 1st, Gigabyte 2nd then MSI in 3rd?

Here is a list of boards I assume I need to buy from overclocking website. I just copied and pasted it, but put time in to add the prices.


ASUS Maximus VIII Extreme Non-K OC BIOS way too expensive.

ASUS Maximus VIII Gene Non-K OC BIOS from $300

ASUS Maximus VIII Hero Non-K OC BIOS from $270

ASUS Maximus VIII Impact Non-K OC BIOS from $330

ASUS Z170-A Non-K OC BIOS from $210

ASUS Z170-Deluxe Non-K OC BIOS from $410

ASUS Z170-E Non-K OC BIOS from $200

ASUS Z170 Pro Gaming Non-K OC BIOS from $205

ASUS Maximus VIII Ranger Non-K OC BIOS from $270

ASUS Maximus VIII Hero Alpha Non-K OC BIOS from $420

--------------- ASUS Z170-K Non-K OC BIOS from $175

--------------- ASUS Z170-P Non-K OC BIOS from $140

--------------- ASUS Z170M-Plus Non-K OC BIOS from $140

--------------- ASUS Z170I Pro Gaming Non-K OC BIOS from $182

K, P, M or I is my price range. Is one model more reliable then another?
I know I have to look at features and my needs to figure out which one I need.

All I really look at is ASUS and Gigabyte mobo's.

I am really lost on whether I should splurge on an i5, thats the reason I looked at refurbished units. Dont really know if I need to overclock anything for what I do, which aint much. But if I can do it for around the same price then so be it. Can OC when the time comes or if/when I need it.

--------------------------------------------------------------------------------------------------------------
I read up on this site: http://overclocking.guide
Here are just some quick notes to remind me;

"Depending on the CPU you can increase the clock between 15-70 % without any problems."

"non-K CPUs have to be overclocked using the BCLK"

"Pre-Skylake CPUs such as Haswell or Devils Canyon could only be overclocked by about 3-5% using the BCLK because the BCLK was still tied to the DMI and the PCIe."

"Avoid high memory clocks. Everything around 2600 MHz will be fine"

"Depending on your budget you should only consider these CPUs:

Pentium G4400
Core i3-6100
Core i3-6300
Core i5-6400
Core i7-6700

All of the CPUs should easily reach 4400-4500 MHz and a high multiplier is not needed because you can compensate everything with the BCLK."

--------------------------------------------------------------------------------------------------------------
Final question is, which CPU is the +70% oc?