Man, I got on today after playing MAG for three days and all my instinctual controller uses are jacked up. Crouch in MAG is triangle, so I keep switching to my sidearm in MW2
Though MAG is infinitely harder than MW2. It's roughly 16 on 16 if you stay in your objective area but the terrain is way bigger. Imagine the Estate map times ten. There are lots of tree-covered hillsides you can snipe from but trails allow opponents to flank and sneak up on you. You have to be VERY careful where you go. Can't just run around. It has changed the way I play MW2. It's almost like hardcore mode.