I ordered new vegas last week, still waiting for it. I got the ultimate edition so i got all the dlcs with it, which raises the level cap from 30 to 50, which is huge. I like new vegas because i know more about it, but i guess it really doesn't matter that much. They are both very similar.

1

...well, if i play nv first i wont play 3, thats like playing skyrim then oblivion.
what do you mean by details, i.e. story line faction plots ect?

Are you asking me to rant? I'd hope so.

My thought on New Vegas, is the gameplay is much wider. Things happen awkwardly, and staggery. As for Fallout 3, the gameplay's straightforward with the exception of side quests/stories, and such. New Vegas has much more to offer with finding guns, tracking certain monsters, choosing different endings via factions. Fallout 3 kinda does that but it's a bit vague. Fallout NV's DLC's are absolutely insane though. I never played 3's DLC but I just think they're both fun. And if you play NV there's no reason you shouldn't play 3 afterwords seeing as they have nothing connected between them.