Since this is a SOW related debate, I would say that NVidia seems to be the best choice for SOW...Otherwise, Oleg would have mentionned AMD's interest in the game ...Be sure that if we have graphic issues with the game, it will fall on AMD's shoulders fast enough...
And about the price...We are talking about $150.00 between the very top GTX580 and wathever is coming under...We have been waiting for this game for about what ? 5 years ?....Its is $30.00 a year that I have put in my piggybank...So, yep, the NVidia is the fastest for the upcomming months...

Salute !