ATi cards were always looked at as inferior, no matter of their performance. Best selling cards in ATi 9xxx and Nvidia FX generation were actually FX cards. They were much bigger, louder, hotter and slower yet they where cards to get here, when in performance ring, it was no contest. They were also late for months and came out factory overclocked with huge fans to keep them from burning your house. Meanwhile 9800pro was beating it with ease, and it had especially huge advantage in AA/AF aswell as newer titles using Shader 2.0.
When I was younger (6-7 years ago) I worked at retail computer shop part time as a student. Basically, 3 out of 5 of my coworkers always recommended Nvidia cards, other one would recommend based on their performance. These 3 would literally say "Just go with Nvidia...". That was a time of GTX400 and GTX500 series. They sold better then much better AMD equivalent cards, I was flabbergasted. I even asked them why are they recommending worse cards for same money and all they said was "Nvidia and Intel are a way to go if you are gaming, thats no brainer".
Even today you have bunch of people on forums saying "AMD always disappoints, they have been losing for more then a decade" "When was the last time they had good chip?". That is rewriting of a history, up until Maxwell, AMD cards were every bit as good as Nvidia counterparts (if not better, considering their design innovations like 360 GPU and unified shaders). Only last 2 gens have they really fallen back, primary on perf per watt. And who wouldn't? With what money would they bankroll Zen R&D, which is make it or brake it for entire company, if not from putting GPU design updates aside? AMD has repackaged Tahiti chips for 2 generations, only Polaris getting some needed updates. Yet, even with all that their cards have held up admirably well. 7970 is beating GTX680 with ease now (was similar back in a day), while 290x/390x are faster cards then GTX970 is. RX480 had ~10% deficit 6 months ago, now its faster card. The newer the title and API, the better RX480 is.
Yes, they have worse TDP. Yes, they run hotter. But AMD has agreement with GF. They are factually using worse fabs then Nvidia because of their contract. Their design and DX11 drivers are probably not as efficient as Nvidias (especially latter), but that tends to happen when one company makes tons of money on slower chips (GTX400 and 500) and other loses on great ones (HD4xxx-7xxx). I will not write off AMD. Their hardware team is still sound and they know how to design good chips. They are working on both high powered next gen consoles (Scorpio and Pro), so they ought to know a thing or two where the things are headed. Zen money is now gone, and Vega probably got biggest R&D budget in years. Who knows what future holds as far as performance goes? AMD is used to making high density chips with hardware that new APIs need. Will Nvidia easily add all that without touching efficiency of their cards? Will they be able to run at such high clocks with new uarch and changed CUDA cores (assuming they change them with Volta?)? Who knows, only thing that is likely to remain the same is the fact that Nvidia, no matter of their performance, will remain "go to" company until AMD marketing team starts doing much better job then they currently are doing.