we did it our last trip (but not the 2 trips before), and are doing it again this coming trip (actually, 3 resorts this time - vero, v@wl & poly)... we leave this coming saturday!!!! of the 2 trips we didn't do it, we were 12 days at GF, and almost got bored there (not actually bored, but the excitement wore off). the other trip was only 5 days, so it was too short to switch resorts for us.
my only advice to someone considering doing it is to end the trip with the resort you enjoy the most and don't go from deluxe to a moderate. also, pack in such a way to not have to totally unpack to feel relaxed. i couldn't relax the first part of our trip, knowing the move was coming. it was because i was living out of our suitcases and doing so uncomfortably. we'll be moving a lot this trip, but i'm packing all shirts on our hangers in garment bags that i'll just hang in the closet. An over-the-door hanging toiletry holder, etc. Keeping it simple should help.
i do love staying at 2 places, i just have to get it down to a science to be able to relax. hopefully this time will be better.