I havent played FO3 or 1 or 2, or tactics, but i accidentally/on-purpose read bits of the wiki and will play them when i have the elusive thing known as spare time.
I did play- and adore/am obsessed with/am writing bizzare fic of- Fallout New Vegas, though. I liked how there was no way to find the "All Good" option because there were some pretty bad things- and some pretty goods things- that all the factions had.
It was full of shades of grey and had a sense that things were finally rising from the ashes of a ruined world into something greater, no matter what option you chose.
I do wish it was a bigger game, though. It felt small, and my previous experience with Bethesda was Oblivion and it's shivering isles expanison. I wanted to really get into it, and i could, but it was over too fast. Too fast meaning almost 200 hours in, but still.
And some of the quests were too freaking easy. I don't know how it is in FO1 and 2, but there were quests that I got really into and planned things out on paper, but never used the plans anyway because the quests and dialogue trees practically gave you the right actions and responses.
Since FONV is very much like FO3 gameplay wise from what i gather, maybe the quests are part of the reason why it could be considered a "dumbed down FPS". And while I love VATS, i can see why people used to playing with either all turn-based combat would hate it.
Anyway, I should probably go play the others soon.