Mass Effect II

If you don't know, I have a PS3 and the Mass Effect II demo for the PS3 came out yesterday.  I have downloaded and installed it today.  Currently, I'm customizing my character and giving it the run through.  Heard it's a fairly involved demo and the only game on the 360 that I wanted to play.  The full game comes out on January 18 . . . I'm excited.  Always love great stories and that's my reason for playing video games.  What do you guys think about the Mass Effect series?