There are a great many reasons to prefer NV, beyond G-sync and SGSSAA profiles. (A small selection: OpenGL performance/support, HBAO+ profiles, TXAA, day one performance on smaller titles, CUDA-supported software, power efficiency, and, yes, GPU PhysX)Then I'd suggest he wait for the GTX 970 and see what that does to prices. I understand Nvidia desire for G Sync (or SSAA maybe), but otherwise sometimes users here come across as either irrational Nvidia zealots, or possessing irrational AMD driver phobia.
That said, I agree with your suggestion to wait with a GPU purchase at this point, unless it's really urgent.
I'm not interested in Ubi's AAAA collectatons, so I haven't played it.How did watch dogs run for you on 4gb?
I got a 4GB version since I often downsample from >4k in less demanding games.