I haven't played New Vegas yet, so I can't compare the two. But I couldn't help but compare FO3 to FO1&2 while I was playing and that's pretty much why I never finished FO3. Everything in that game annoyed me. In the beginning when it is walking you through the tutorial and they made you shoot a rad roach with a BB Gun or whatever (been a while since I played), I restarted the game because I thought I had accidentally made some kind of decision on what kind of character I wanted to play at that point. Of course, I was wrong, those decisions weren't until later and they were basically forcing you to kill something right away. Man, that annoyed me. Really looking forward to F:NV to try a pacifist run, since, y'know, Obsidian will let me do those kinds of things. :p
And then there was the terrible writing. Ugh.
Yeah, if I had gone into FO3 not knowing anything about the Fallout universe or the previous games, I probably would've enjoyed it. Ignorance is bliss I suppose.