My next card will be a Radeon 300 series. After that, I might switch to Nvidia just to see how it is, since all my experience with AMD graphics cards has been very positive.
I'm getting constant over 30 FPS with everything maxed out, except Nvidia Hairworks (which are set to off) and foliage distance set to high (this option seems to impact performance the most).
When I was preloading The Witcher 3, I was getting the same download speed I usually get on Steam, so that's fine.
I had no crashes for now nor have I encountered any bugs except play time not changing unless I restart GOG Galaxy.
I never had performance issues with it. And that's quite interesting since my build isn't as powerful as your's.
I've stopped playing at about 60 hours since I got bored and never really wanted to buy premium, but those 60 hours were good.
With a $2000+ rig you can play all those games on ultra at 60+ FPS constant.
Also check out the video Stijncat mentioned, it might be helpful for you.
EDIT: Since Google did not convert pesos to USD the right way, ignore everything I said.