AMD and NVIDIA both have different problems with FF7 modding. And in general.
Personally I'm not a big AMD fan. In pretty much all cases, I've had nothing but trouble with their drivers. Crashing, constant reinstalls... it ain't worth it to me. Of these two cards, the AMD is easily the more performant, but if I were buying I'd still go with NVIDIA. That said, if you use Linux AND prefer to use open-source drivers, AMD is a far better choice; but if you're on Windows, or if you want to use official Linux drivers, I'd definitely recommend the NVIDIA option.