I love it. Can't get enough.
It's not a groundbreaking game . . . and it doesn't have astounding design or new art that's going to change the way you think about computer games. But it's mighty solid and very refined. They've streamlined a lot of the annoying inventory management, so it's a lot simpler (it's ok, if you want inventory management in a long bioware RPG, you can still play Dragon Age :P) than its predecessor. The gunplay is quite satisfying and the flow of the game is good.
The only downside is the amazingly grindy mining minigame that you play while exploring random worlds out in the universe. That is one of the worst time fillers I've ever seen in a game. It's astoundingly bad . . . and very annoying that you have to do a certain amount of it if you want certain positive outcomes in the game (I'm being vague to avoid giving out spoilers).
The morality system is kinda funny. I find myself walking around in everyday life trying to figure out how I can help people to earn Paragon points (In the game, your decisions earn you Paragon points for helping and looking after people and Renegade points for taking a "end justifies the means" approach to problems). It's all about computer games helping you be a better person :P
The characters are a lot more interesting than in most games, each with their own back story and gameplay style, and as opposed the the first game, you're actively encouraged (even forced) to play with different squad members and to use your whole team, not just 2 chosen team mates.
I've played the game through twice, to check out different character types and morality decisions (although the different decisions didn't really change the storyline at all) and thoroughly enjoyed it.