I did not like the original Mass Effect enough, it was seriously bugged and got repetitive/boring after a while for me.
I however did download the same Mass Effect 2 demo for my new Windows7 PC and it left me completely cold.
I haven't had the time to complete the demo, but on the PS3 it felt a lot better for me. I guess this has mainly to do with more comfortable wireless gamepad controls vs keyboard/mouse I was using, connected to big ass HDTV vs much smaller PC monitor and I have my PS3 connected to a great surround audio setup. That makes a huge difference for me! I liked it. 
It felt better than I expected and I look forward to finish the demo tonight when I get home, although I don't think I will turn into a fan of the series, a far cry from my anticipation for games such as LittleBigPlanet 2, Killzone 3 and Uncharted 3.
