AMD Ryzen 7 1700x/1800x or intel 7700K for gaming/editing/using apps like autocad or blender

Ryzen. For either choice, you'll get good performance, that's not a consideration. The i7 only beats the Ryzens by a few fps at minimum frames but can enjoy a somewhat larger lead at maximum frames, which really is of no consequence. Make exactly no difference to a 144Hz Monitor if max frames are 200 for Ryzen or 300 for Intel, only the minimum frames really count, and if both are above @150, game play is still buttery smooth. So gaming on either is pretty equitable. In reality.
But not so in productivity apps. Here the thread count is clearly in Ryzens favor, some apps enjoying almost double the ability of the i7, so doing a heavy render taking the i7 an hour could take the Ryzen @30minutes. That's a huge discrepancy in reality. Do 2x or 3x renders back to back and you go from having to occupy 3hrs to only 1.5Hrs, and if time is a valuable commodity, that's going to get expensive.

So you'll have to decide what's more important, a benchmark, max fps superiority in a few games or time saved on production.

Personally, the Ryzens are superior for all-around performance, for your needs.

AMD Ryzen is less good than i7 7700k only because games are not optimized for AMD Ryzen.
For future, AMD Ryzen rocks.
BTW, I would go only for 1700, instead of 1700x or 1800x, and OC the hell out of it.

Note:
I am also in the planing to replace my E3-1231V3 with one of those Ryzen 7.
I Ave set my eyes on 1700.

There's no simple explanation, or short answer or really any definitive must follow plan. Google a bunch, wiki every setting you are unsure about. Watch every video you can on the subject, especially that which pertainsto your specific motherboard. OC Ryzen in general isn't hard, the theory basically applies to any mobo, but different vendors have different names for some things like one brand might be VCCSA, where another brand might call it System Agent. Same thing, different name. No worries.
Mostly OC is trial and error, every cpu itself is slightly different, since the silicon it's made from is slightly different, so might respond differently slightly than the videos. So you'll get a lot of 'try this', nope didn't work, reset that, 'try sumptin else'. A visit to the Asus ROG forums will have a wealth of info as those guys really tweak a cpu to its fullest and love to brag.

As to the Asus maximus. Just about every single speed record, be it air, aio or full custom loop, even liquid nitrogen, for the last 20 years or so has been done on an Asus maximus motherboard. So when ppl have said that you need that board, it's more that it's pretty much a given that that board will not be any kind of hinderence to OC values. So if you really, really wanted to get 4.6GHz on air that would be the board to take you there. Most other boards don't come with that kind of pedigree, not to say they are bad, but ppl who own the Asus boards are basically trying to take it to the edge, ppl who own other brands are basically happy with a decent OC and call it a day. Do you need that board? Maybe not, you don't strike me as a need for speed kinda OC junkie. Any of the x370 will do, as long as it has the connectivity you are wanting, like good lan or multiple m.2 or a certain amount of fan headers. The top line B350 boards are almost exactly the same as the middling x370 except for 1 major thing. The B350 only supports a single gpu, no no crossfire or sli will be possible. If that's something that's a decent possibility, go with the x370. If that's not really a consideration, a single gpu being more than sufficient, then a good B350 would be cheaper.

The plans of mice and men.... I go into my bios probably 2-3x a month, minimum. I've got 3x OC profiles I play with, 4.3GHz, 4.6GHz and 4.9GHz. There's times when temps are climbing when I'm at 4.9 and I know it's just because I've been lax on cleaning, so I'll cut the OC back to 4.6 for a week or 3, if it's bad enough, even 4.3 for a while, cuz I'm a little OCD about some stuff, so it takes me a good 3hrs to really make my baby shine. I just need the time to do it, so I'll put it off till I can. Sometimes I'll mess with using the gpu in conjunction with the igpu when trying out a new game, see how it does for cpu/gpu usage and if the picture is better, that requires a trip into bios to enable the Lucid software. Taking a trip into the bios isn't much different than popping the hood on a car, everybody tinkers every now and then, best part is that no matter what you play with, unless you actually, manually save the setting, it won't apply to boot. At all. So you can't mess up a bios unless you do it on purpose.
Also, amd and it's partners release upgrades and optimizations every now and then, so it's entirely possible that you'll take a trip into the bios, just to get that extra few % bonus performance for free, which could very easily mean time saved on a project or a few more fps on a game etc.

I wanna add Information too:
Overclocking processor is not only depending on the mobo, PSU, cooler, etc.
You need also luck. If you got a very good sample, you can OC it high....if not...then...accept it or sell it then buy a new one
e.g. My old Q6600 @ 3Ghz no matter how I tried. Other People can reached 3.3Ghz or even more.
Ryzen should be no exception.

Note: I have not tried to OC any Ryzen yet, I have never touched any of them yet...they are new...

You may have to pick and choose which programs are your priority. Both would do well, each have their strengths. In pure gaming, the 7700k performs better than ryzen. The 7700k also performs significantly better in autocad than ryzen does (close to 60% faster). On the other hand ryzen performs better in blender by around 30%. If you plan to do other things like stream your gameplay ryzen may be more beneficial but with a 1080ti you're likely better off using shadowplay either way.

Autocad
http://www.tomshardware.com/reviews/amd-ryzen-7-1800x-cpu,4951-9.html

Blender
http://www.anandtech.com/show/11170/the-amd-zen-and-ryzen-7-review-a-deep-dive-on-1800x-1700x-and-1700/18

As others mentioned, both cpu's can be overclocked but it depends on the cooler, ambient air temps, case cooling, luck of the draw on the silicon lottery. I don't believe anything's changed, ryzen seems to top out around 4ghz and won't oc higher for just about everyone. How far the i7 will oc depends more on the silicon lottery and cooling but should be able to oc it a bit.

Anandtech was able to get their 7700k to 4.7-4.9 ghz depending on avx offsets.
http://www.anandtech.com/show/10968/the-intel-core-i7-7700k-91w-review-the-new-stock-performance-champion/11

Some folks here were hitting 5ghz to 5.1ghz on their 7700k's.
http://www.overclockers.com/forums/showthread.php/779171-*OFFICIAL*-Kaby-Lake-Overclocking-results-thread!!!