Early benchmarks are favoring AMD in directx 12.
However DirectX 12 games do not exist so people don't look at that. They look at the present. And presently NVidia uses less power. GSync is also better than freesync. NVidia has 3d if you're into that. NVidia has a history of fewer driver/game compatability issues and bugs. People who have had past issues with AMD are now Nvidia fans. Crossfire has a lot of tearing issues. All this boils down to a lot of NVidia fans.
A lot of games have the splash screen that says "optimized for NVidia. I hope you didn't buy an AMD you dummy." So people with AMD feel left out. I don't remember the last game that said "optimized for AMD, you're shit out of luck if you bought an NVidia."
Also AMD is loosing the CPU battle big time. Intel is kicking butt on the CPU front. Also Intel LAN is considered the best on board LAN for motherboards. All laptops are pretty much Intel. Also a lot of the small PC's on a stick/box like a media player are Intel based. All the NAS' are Intel based. Intel SSDs have a history of being the best and most reliable, although expensive. Point being, Intel has a good brand reputation and recognition. A lot of people diss Radeon because they don't like AMD cpus.
NVidia has a lot of brand recognition with mobile video and processors. And the new Android shield being the best. NVidia has a good reputation like Intel and that's the reason you see it recommended so often.
If AMD's new ZEN can give it a real boost with DirectX 12 and their Radeon cards looking like winners, I think AMD is going to gain some much needed momentum. 2016 will reveal a lot.
Those purchasing today are going the Intel skylake, DDR4, and Nvidia route with a G-Sync 144Hz monitor, and I don't blame them. It's the best solution going. I'm an AMD fanboy myself, however not an Intel hater, so hoping AMD wins the race. At least AMD doesn't rape their customers when it comes to black edition CPU and unlocking multipliers. They are very fair.
NVidia has a habit of beaing ruthless. They tried asking benchmarking softwares to remove certain DirectX 12 features so their cards wouldn't look so pathetic. I think AMD has a big 2016 ahead for them. I'd go Radeon and hold out for AMD Zen CPUs and motherboards.