I find that....Fallout: New Vegas is a lag/glitch/bug fest, just like it's brother, Fallout 3. I haven't played Black Ops yet, but if it doesn't freeze every couple of hours, then it's all good. :P
i persanoly think that you cant compare the two since one is a free romeing rpg, and one is a strait forward shoot um up war game, sooooo, i gess that if i had to choose, id choose black ops-killbynight