I love Doom, Duke Nukem 3D, Tuork, Blood, etc, but can't see the attraction in Quake. I just found it tedious and un-enjoyable. I'm only talking about the single player in all these games, really. But Quake was dull, I thought, with levels that all looked the same, had no interactive scenery, and whose sole plus point seemed to be that the engine was genuinely 3D. But I much preferred say Duke Nukem 3D's visuals, as even though the enemies were 2D sprites and the graphics warped when you looked up or down, at least the levels looked varied and interesting. But even leaving aside the graphics, Quake was just no fun to play, I thought.
But the magazines of the time loved Quake, and gave it tons of publicity whilst largely ignoring the DN3D, Blood, etc, scenes. And most PC gamers seemed to love Quake, so I am in the minority there, I know.
As regarding 2.5D vs 3D FPSs, I don't prefer 2.5D FPs as such, but I prefer their ideology to the ideology of FPSs released in the last decade, as the best 2.5D FPSs, along with many of the best 3D FPSs of the first half of the 2000s, are designed with replayability in mind, so there are secrets to find, are not too linear, and want you to find your own way through the levels instead of giving you a single linear path to follow.