While I think the burgers are good, I wouldn't say they are the best on property (but, then, I prefer a thick burger to a thin one). I prefer the burgers at Yacht Club Galley which is virtually next door to Beaches and Cream and unless there's a big convention in house, usually has very little wait to get in for lunch. The big advantage though is that 9 times out of 10 you will get a cold/lukewarm burger at the CS locations and the one at B&C will be fresh, so it does taste much better than your typical CS. However, if you are in to ice cream sundaes, B&C is definitely worth a trip. I agree with asking about counter sitting, as they will often seat you faster at the counter (and people don't linger there as long, so the seats open up sooner). There is also a take out line where you can get ice cream, which if there is a wait for the restaurant may get you your treat much sooner.
I agree that you should try to plan your visit right around opening time to minimize your wait time.