All i can say is that i had a game of Fallout 3 going recently with about 120 mods running and it was great but sometimes very unstable, as i had a lot of mods running together which conflicted with eachother. FO3 was also not very stable to begin with so i put up with a lot of ctd's.
New Vegas on the other hand needs much less work to get to a spectacular level. The modders seem to have put extra effort in to making their mods as compatible as possible and they are much easier to install.
Modding New Vegas is an absolute breeze compared to FO3! I have not had a single crash or freeze or anything in 10 hours so far(compared to FO3 where i probably had dozens of crashes by this point)
Cheers for the Info I guess I will Mod Vegas then