Hi guys. I'm in the program currently. Coming in, I'd finished about half of my requirements (1 yr bio, 1 yr gen chem, and 1 semester orgo) before entering the program after graduating from Penn in May. I'm completing the rest of my requirements part-time and this hasn't presented me with any problems. In fact, the advisors have been really nice and seem to understand that not all premed students can just take a year out to take classes (i.e. that some of us have to work as well). However, I think if you're looking for a really tightly organized program this might not be the one for you. There's a fairly tight post-bac group for the full-timers and admission workshops, viewing sessions, etcetera, but there's not really a formal curriculum (i.e. not a set "you must take these classes or else" schedule). Also, when you come out of the program the only thing you really get are your course completions, hopefully a higher GPA, and a committee letter. So, if you feel like you'd feel better knowing you earned a masters during your off year, it's not the program for you. Still, I like it and I think if you just need to finish up requirements, improve your GPA, and need some flexibility, it's a great way to go.
Good luck.