We have only done online check-in. I know the perks of doing this but are there any perks to waiting till you get there? Do you have a better chance of getting the building/floor that you want by waiting or do you have a better chance with online check-in? What does everyone else do?
Your chances are totally based on occupancy and what is available- so I can't imagine any scenario where waiting until you arrive to checkin has a benefit. When you get to the resort and have done online check in, if there is a problem you can always ask/try to move rooms. #1 thing I hear is to fax a request the week before.
I have heard of no situations where it is better to wait to check in until you get there. On-line check-in primarily takes care of administrative tasks, like credit card details, and isn't really related to room assignment (other than giving you another opportunity to indicate room preferences).