I greatly enjoyed fallout 1, 2, 3, and vegas.
However, to me, 2, 3, and vegas were just games. Good games, but they lacked the genuine thoughtfulness and artistic merit that had been poured into fallout 1.
All of the other games in the series have a terrible issue with the major choices in the game either being completely illogical, or ultimately a whim. It's choice for choice sake, which is no different from choosing a hat. The enclave is blatantly made out by the games as being a bunch of cartoonish super villains. I can't remember a single redeeming quality that the enclave possessed. As far as I know, the player is never once able to side with them, but even if they were, there wouldn't be any rational reason to do so. It gives the player options, but either gives them a very straightforward "correct" (either morally or mechanically) option, or it really doesn't give the player an incentive to choose any option. Everything the player does is either because the game forces them to, or for the random hell of it.
Where as fallout 2, 3, and vegas all were a canvas for the player's whims, generally lacking in almost any meaningful conflict, the original fallout is one of the few games that I can think of that actually tries to probe the player's sense of morality. It does this with the most frequently hated part of the game: the time limit. Now, I have to admit that the time limit was ultimately just an annoyance, but that was because it wasn't strict enough, not because it simply existed. What the time limit adds is a permanent consequence for for choices. It's no longer a question of whether the player wants to be good or evil, but whether they want to be expedient at the cost of causing suffering and death to others or if they want to try and help as many people as possible at the risk of failing their primary quest. This could have been improved if failing the main quest hadn't caused an instant "game over," and the time limit was about two thirds of what it ended up being, but the point stands.
Sure, the player could waste their time helping a bunch of ghouls in exchange for their water chip, or they could just take it. It's for a good cause, right?
Sure, the player could help the corrupt mayor for a quick and easy reward, or they could use up a lot of time helping some people that the mayor is using as scapegoats. There are more people in the vault that are at stake though.
Sure, the player could try negotiating with the raiders for the safe release of the chief's daughter, but at the cost of a great deal of money. If I remember right, the player isn't compensated for even close to what is required to barter for her safe return.
The other games never forced me to actually contemplate what I was doing or question why.