Did this last year --- LTT PS before MVMCP and it was awful. Got there 5 minutes before our PS, waited over an hour in the EXTREMELY crowded lobby area and never got called. The staff was harrassed, frenzied and, not suprisingly, unfriendly. After an hour of trying to amuse my very hungry son, 2 1/2 years old, we left and went to Columbia House.
Our PS was around 6 or 6:30 so I would stay away from those times because I think they get backlogged with folks trying to "kill" the time until the parade or rides open back up or whatever.
Loved MVMCP though!