I was a big ATI fan until I got my recent GTX 460. ATI can do well for lower power and mobile GPUs.
GTX 460 is the only Fermi worth buying. ATI's 6800-series is really pushing it though. nVidia's issue seems to be that they cannot deliver a balanced lineup, only one or two decent GPUs.
Sure there are some features that are nVidia only but ATI is the winner of 40nm roundup. Hopefully 28nm will be a better fight. nVidia just needs to be faster, it's not worth it to release DX11 GPUs almost a year after ATI as most people have already done the switch.
Hmm, ATI is joining the infamous renaming game linky