I loved 1,3 and 4. 2 was terrible.
Personally, I think 2 has the best gameplay in the series. MGS1 has the best camera, and 3 has the best writing. 4 has the worst everything.
MGS21? I always thought MGS2 was the only game in the series to have a perfect camera. It worked beautifully within the environment they created. It was definitely the most polished MGS game released.
What baffles me is why they didn't adopt an MGS2 style camera for the PSP games. It seems like a natural fit!
Don't get me wrong, MGS2 is still my favorite in the series, but the camera in MGS1 is extremely reminiscent of the 2D MG games, and MGS kind of plays like a 2.5D game.
I can't imagine how a fan of the series would dislike MGS2. It's probably the most polished game I've played, period, let alone within the series. And even now, the visuals are something special. Sure the story is complete shit, but I completely forgive it for having some of the best gameplay and most genius sword mechanics ever.