I'm hoping it is more like ME1 then ME2, but I'll wait until it actaully comes out. ME2 felt more like gears of mass effect to me then a proper RPG.
The ability system is a nice combination of the two. Combat is very ME2, which is a good thing. The demo doesn't give you enough to judge how deep or shallow the RPG mechanics are, however it does look like it's somewhere in the middle of the two.