Have worn my MAV with packs small, medium, and "is he packing a midget", the wearing isn't a big deal. Now, with the depth of the pockets I've got on my MAV, getting the waist belt open is sometimes a bit tricky, but not too major.

And whatever you do, keep the chest rig CLOSED when you are taking off your pack. If the pack wants to take the chest rig off for you, you end up a bit tangled. You'll only make that mistake one time though.