Been playing a bit, I'm up around level 15. So far I guess I'm a little underwhelmed by this sequel. Yeah it's fun, I'm definitely hooked. And I just LOVE the graphical style of this game. But it's pretty darned similar to the first game, they really haven't added anything new in terms of game play. Sure the characters are different, but it's still the fundamental choice of character type: commando, sniper, "magic" user, brute gun slinger. There aren't quite as many missions, it seems, and each mission is longer and more involved than they tended to be in BL1. Which is kinda cool because it gets you a little more involved, but kind of annoying sometimes if you're a compulsive swag collector like me

and you have to go longer between vending machines to sell all the crap you've picked up along the way. I still spend way too much time in inventory management, comparing stats between various weapons, etc. Hard not to be obsessive about that, for me anyway.
Oh well, I still love it, and I don't mean to knock BL2. If you loved BL1 you'll love BL2 as I do, just don't expect anything terribly different; they've found a successful formula for this game, and are sticking to it.