The self-paced thing worked for me primarily in math courses. I failed Chemistry in HS because of something math related, and had to repeat Trig, so I got the idea that I was "bad in math". When I took self-paced math in college, I realized I could grasp the concepts, just not in the way that I was being taught sometimes. I changed my major when I realized that I could actually manage higher level math.
I graduated right dab in the middle of my HS class, and that was only because I did so well in heavily weighted AP History and English classes. I got high SAT and ACT scores too, so I got into every university I applied to. Nonetheless, I flunked out of my university of choice my first year, but more due to depression than anything. I went back though, but it took me 6 years and 3 major changes to graduate.
Sudbury Valley doesn't grade students, and they can learn what they want, how they want. There are no formal classes. The students have to present a thesis in order to graduate. They can get someone to work with them, or work alone on any given day. The kids essentially run the school by a vote during a town hall meeting. Almost all of the students go on to higher education, and get their degrees. I always found that to be pretty interesting, considering they come from a school in which they aren't required to attend any formal lessons.