Ok I am going to step into the fire.
I love online check in! KNOCK ON WOOD We have gotten every request we have made since we have started using it both
DVC and non DVC.
Pop Century - requested king bed, got king bed (in the past we have requested it and never got it)
POR - requested building close to main building, got building 18 (before it became preferred, and again have made this request before and never got it)
BWV 1 bedroom - requested 4th or 5th floor, end of hallway for view of the fireworks, got it.
BLT MK studio - requested highest floor available, got 8018, 10th floor, GREAT VIEW.
I have travelled to disney every year these last 10 years, multiple times usually, and before online check in we almost never got our requests. Once online check in started, and we tried it (after a CM at Pop Century recommended it), we have become die hard fans.
Of course I also usually fax our resort requests in too, in addition to adding them to our reservation. some may say it doesn't work... but it works for us.
Thats our take on it atleast
Jennifer