Started playing this on Saturday. It's frickin' ace! Improved on ME1 in every way.
SPOILERS!!!!!!!!!!!!!!!!
The only thing i'm not keen on is the planet scanning (which can take a while, even after the upgrade) and the inter-galactic travel with fuel reserves. But i can live with it.
The characters are so much better too. Kaiden and Ashley were meh, Tali and Liara were OK, Garrus and Wrex were wicked. Grunt basically takes Wrex's place, Samara is a definite improvement over Liara, Tali is Tali, Jacob and Miranda are upgrades of Kaiden and Ashley, Archangel is Garrus so he's still in and still kicking ass, then you have the extra characters who are sheer badass, Jack and Thane. More choice, and deeper personalities. Much love.