Checking in early is often preferable to checking in later!!! Sure, you might not get your room, but the lines are not nearly as long. And the earlier it is, sometimes the more pleasant people are.
I will say that until you have checked out of a resort that was almost completely full, with most of those people trying to leave at the same time..well, you just haven't lived!!! When we left POR on June 26, it seems that all the Pampered Chef people there were leaving at the same time!!! Man, it was crazy!!! The pool guy that came for our luggage that morning was frazzled. He said he had been working since 3 a.m.!!! But, he had a great attitude. Evidently Pampered Chef was having some kind of reward convention trip the same time we were there. I couldn't figure out why I kept seeing all these PC teeshirts everywhere. And a lot of those families were at POR!!! Housekeeping was most likely out straight trying to get all those rooms ready to turn over!!!!
But again, POR is one of my favorite resorts. It was my first WDW resort and I most likely expect to have the same experiences that I had back then in '99. But, that isn't going to happen. For the most part, my time at POR have been wonderful. Can't wait to stay there again!!