I 100% do NOT recommend playing the second one without playing the first one, no matter what the developers tell you.  Go pick up the first one for $15 used and then play the second one.  You'll thank me.

I'm loving it so far, although I'm not too far into it at the moment (damn Uni work getting in the way!). Playing on PC using my character profile from the first and I love seeing how the decisions I made in the first are affecting my game in the sequel.

Pros

- Improved gunplay: In the first I almost felt like the shooting was tacked on. In this one it's a lot smoother. Almost a Gears/Uncharted feel to the dynamics.
- An interesting assortment of characters (so far at least). They don't all fall into Bioware's usual "crowd" and sterotypes.
- Interesting story. Not the best story (so far) in games (specificall RPGs) but more than enough to keep me playing.
- Much faster loading (PC version) and just overall, better optimised. It runs perfectly on my PC and I've had no problems so far. The first one had a few even though it looked worse, which brings me nicely onto...
- Graphics. A huge improvement over the orginal. I wouldn't say they're near the top graphics of the gen, but very good nonetheless.
- When finding minerals you no longer have to land on a planet and drive the stupid mako, in fact, I haven't seen the Mako at all in this one, yay!
- The galaxy map is actually kinda fun now :P

Cons:
- Huge reduction in actual RPG elements. Less skill points, can't always see how much of an improvement one particular weapon is over another etc.

Overall it's a great game. I'm not sure I count it as one of the best RPGs out there based on the little I've played so far, especially with how simplified they've made it, but it's damn good. The best shooter-RPG hybrid of the gen!

Agreed---they made a conscious effort to reduce the time spent messing around with your weapons, but I actually LIKED micromanaging all my weapons and armor in the first one, so the fact that it does all that for you is a little disappointing.  The time they reduced in that area is just spent mining anyway!!

Otherwise awesome awesome awesome game.  I am loving it.  

Great game don't get me wrong. Technically brilliant and the voicework and conversation system are second to none. Maybe I'll get more into the gameplay as I replay but it's not what I was hoping for in the series. Saeed, Jack even Miranda are not who I'd want watchng my back. Samara and Thane are my favourites. Miss the feeling of an open universe that the first game had. This game is pretty linear and takes away a lot of the feeling of choice. Hate getting blown out of cover and killed before it lets me move again and I hate having my vision obscured just when I need it most. I won't be playing this a dozen times.

It's better then Uncharted 2

http://xbox360.ign.com/articles/106/1064323p1.html