Well.. you might want to know that if you are into modding and stuff and put high textures on everything then the 7950's 3GB VRAM would be very good for someone like that.
I mean when someone plays Skyrim with High Resolution Texture mods and every stuff, then 2GB RAM most often feels less, just because as soon as the VRAM is filled up, there are frame drops. So, I think the 7950 should be better.
But anyways it is better to wait, and then let hardware sites release benchmarks and then it should be a good comparision. If you can wait, then that is better.