I think New Vegas was a far better game than Fallout 3. Its game mechanics are far more refined and the New Vegas world was more interesting. Fallout 3 had better set-pieces and perhaps a somewhat more coherent story, although New Vegas had more interesting characters and scenarios to interact with, and it's not like either game was Shakespeare anyway. The only last-gen games I'd rank higher than New Vegas and Fallout 3 were Valkyria Chronicles and Ni no Kuni.