From what I've read and heard, any games other than Fallout 1 and 2 aren't worth playing.
Don't know if Voll or VD can back me up on that.
Fallout: Tactics was an abomination, and I've never touched Brotherhood of Steel.
These were basically seen as milking the franchise by serious Fallout fans, which is one reason why Fallout 3 is such a big deal. They've got a lot of expectations to meet, but I don't think it would be difficult.
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