Well I loved the demo.
Are the upgrades a bit like COD's perks? Sure, I guess.
But the ability to change the suit's use on the fly, from stealth to armor, was just awesome. The use of energy required to do those things was quite balanced, especially considering that sprinting, and high jumping ALSO uses energy, so nobody was 'overpowered' in the demo.
I will say I loved the MP of the bug-ridden demo more then I loved the best COD MP. Why?
Because the way people traveled around the level was dynamic! You could grab ledges, jump on top of buildings, and actually move around the level, rather then just through it. If I look down an alley in COD, I know that they can only come down that alley. In Crysis 2, they can leap up on top of the building, run above me, drop down behind me, and snap my neck. That is way more interesting.
I'll be looking to get this one pretty quick after launch, if not day 1.
I had a blast with the demo, and can't wait to play the full title.