I played MGS 2, and so far I'm the only one I know who really enjoyed it. I thought it was great up until

[spoiler] Everyone went insane at the end and you destroy like three metal gears with a rocket launcher. And get a sword :S [/spoiler]

But overall, a great game, I'd say finish it off. If you're not very far into it then maybe you just haven't hit any really good parts yet.

EDIT: And as for 3, once again, another great game. Significantly harder though, so if you're liking more of a challenge, play this too.