AMD systems are fine. There's no special trick to them as far as the user is concerned, you just run games on them like an Intel PC.
AMD R7 CPUs compete against Intel i7s in terms of price /class.
AMD R5s like the 2600x compete versus Intel i5s for price/class
The performance for gaming at 1440p between an Intel i7 8700k, an AMD R7 2700x, an Intel i5 8400, and an AMD R5 2600x is actually almost non-existent. You would not notice the difference between any of them playing games. They're functionally the same.
If you compare the averaged out performance of an AMD R5 2600x and an Intel i7 8700k at 1440p:
You will note the R5 2600x offers performance within about 3% of the i7 8700k.
Or comparing specific titles, Witcher 3 and Hellblade:
in Witcher 3, the i7 8700k gives 104.2 frames per second. The R5 2600x gives 101.2FPS. 3 frames per second difference.
In Hellblade (which is awesome btw) the difference is 1.2 frames per second - 85.4 vs 84.2.
Your eyes won't even be able to tell the difference, especially with a gsync monitor synchronising refresh rate to framerate.
But you will notice the extra £200 missing from your wallet with the Intel system.
Actually the performance difference will be even less for your system because the i7 8700 (non-k) is slower than the i7 8700k - and techpowerup are also using a more powerful GPU in that benchmark, whereas your system will be more GPU-limited (which is normal for games)
AMD were lost in the wilderness for many years, with the FX series of CPUs being mediocre at best, and their Phenoms quickly losing ground versus Intel's Sandy Bridge in 2011/2012. This is probably why you've never had an AMD system.
But their Ryzen series of CPUs are frankly putting Intel to rout... Intel only released 6 and 8 core mainstream CPUs in response to AMD's Ryzen. Intel has been beset by security vulnerabilities in their CPUs (which affect AMD's ones less), and may even get leapfrogged by AMD next year due to their 10nm CPUs being plagued by years of delay. Intel have also hit supply problems lately which have caused their CPU prices to skyrocket.
Thanks to this, AMD may regain a 30% share of the desktop market versus Intel by the end of 2018. Which would be higher than any time since 2012.
i.e. AMD are pretty damn competitive at the moment, which isn't surprising when they offer a functionally equivalent product in gaming (and a better product in some other spheres) for a much lower price.
My systems have all been Intel too since 2004. My next one may well be based on Ryzen 2 next year.