I applied and was accepted to the U.Va program last year, but attended another program. Take what I say with a grain of salt, since things may have changed in the year since I applied.
The program is run through U.Va's continuing education school and students take classes with regular undergrads. In the case of general chemistry, for example, that means taking the course with about 400 other people. The anonymity and lack of personal attention by professors didn't appeal to me, and I also felt like the person running the program (I forget his name) didn't know as much about the whole med school applications process as I would have liked. Though I didn't visit for an interview, classmates of mine at the program I ended up attending (a more well-established and smaller formal postbac) mentioned that it seemed like they were still hashing out a lot of the details beyond the basics (i.e. taking the necessary prereq. classes and prepping for the MCAT).
Perhaps someone who attended the program for 2006-07 can comment? I'd be curious to know how it went for you.