SR2 has its problems but as far as I'm concerned it's better than SR3 in pretty much every way, from quality of humor and writing to gameplay and things to do. I feel like at any moment I could be doing one thing and something else the next. SR2 feels like I've barely scratched the surface of things to do at fifteen hours in.
All that's left to do are some snatch missions, a few shitty heli-assault missions, and finish upgrading all the way.
No fancy new clothes, no cool new stores, no nice new weapons, no good side missions, nothing. There's just more of it, for one - I spent fifteen hours in SR3 and I feel like I could drag nothing more out of it. Saints Row 2, on the other hand, comes across less enthusiastically at first but is ultimately a better game. I just wasn't having fun and wasn't looking forward to, well, anything during the last hour. I remember getting to the endgame and thinking that even Bonnie Tyler's humorous playing of 'I NEED A HERO'! wasn't funny at all. I just found that Saints Row The Third has less entertainment and it hits a point where it isn't that much fun anymore.
I like some of the things in Saints Row the Third, and I think the craziness is pretty fun, but ultimately I think that Saints Row 2 is the better game.