I think there are some differences. In my school (overall ranking Top 15 & B-school ranking Top 20), Part-time MBA program is much easier to apply than full-time program... (e.g. Average GMAT is 620 for PMAB VS. 698 for MBA, acceptance rate is over 60% for PMBA than 28% for MBA, etc..)... And some professors do not teach for the evening class (but most of professors do)....