Comparing the game to Modern Warfare 2 might not be the fairest thing to do, especially considering the demo status of Bad Company 2, but I don't really think Modern Warfare 2 is really past its beta phase either.... Here it goes anyways:
Modern Warfare 2 feels a lot heavier, maybe more stable, while Bad Company 2's controls feel kind of flighty at this point. The way the cross hairs float up doesn't necessarily tie directly to the shots you're taking, unlike MW2's gun shots giving recoil and placing your sights back down slightly further up, instead of simply floating up and staying up.
Of course, you can't exactly hop in a vehicle and tear across the landscape in MW2, but Bad Company 2's vehicles seem to balanced a little weak. The turrets on defensive positions shred the tanks and other vehicles a little too easily. Even with secondary pilots manning machine guns and the like, infantry make short work of vehicle in any shape or form.
I wonder whether or not Bad Company 2 will actually take any of the shooter audience away from Modern Warfare 2. Of course, the console crowd may migrate from one title to the next, but I can't see it happening so easily. If MW2 can't be patched and the experienced tightened and expanded in the right ways, Bad Company 2 will take the cake and run with it, especially after the way Battlefield 1943 captured the shooter crowd this past summer.