I went to a session there and my impression was that the program was heavily oriented for working professionals. There were a few students that weren't working, but they were doing internships many hours a week out of school.
I have also had long conversations with current students. MPP and MPA seem to be very similar at GWU, so I don't think there is a difference in their schedule.
If you are looking for an intense, academically oriented program, GW is not the answer. But if you are interested in working in DC, developing your network here and having a diploma from well ranked school, GW may work for you.