I did GTDT, and I really enjoyed the flipped learning sessions. The learning style is much more independently driven, in that you really get out of class what you put in. If you do a good job staying on top of material, then the flipped sessions serve to test and reinforce what you know, and help inform you of what areas you need to brush up on. I personally do not get a whole lot out of sitting in lecture, since I tend to space out occasionally, and the material moves so quickly in lectures that I find myself lost! Besides, my engineering background's taught me that I work much better in small groups, and the learning style at GTDT facilitates that.
I really enjoyed explorations. You don't get to decide what you do, but the experiences span a huge range of things ranging from police/fire department ride-alongs, volunteering in soup kitchens, all the way to shadowing various doctors. I felt that it helped give context to all of the physiology I learned in class, and it reaffirmed my desire to go to med school. GUMC students are free to pursue opportunities on their own, but GTDT has a day every week blocked out for rotations. Additionally, it's much easier getting shadowing via someone advocating, scheduling, and jumping through bureaucratic hoops for you versus cold-emailing doctors at hospitals yourself. Generally, GUMC has non-mandatory class 4-5 days a week, versus 3-4 mandatory class days for GTDT. The experiences helped inform me of some of the issues patients deal with at every level from community, to emergency services, all the way to the physician-patient relationship.
If I were to do it again, I would do GTDT in a heartbeat. I really loved the close relationship with faculty that I had, and I felt supported by my peers and professors. For housing, the GTDT campus has unparalleled bus and metro access. I had classmates live as far as Ballston and Bethesda, but I also knew people who lived a little closer in Shaw, H St NE, and Chinatown. You mostly just have to shop around and find a place that works for you.