I completed MAPH last year and have now been accepted, in English, to PhD programs at Virginia, WashU, UCLA, and Michigan. I have MAPH friends who have also gotten in (again, in English) to Berkeley, Penn, and Princeton. So it does seem to be a useful program, anyway, for those who are interested in continuing their graduate study.
It was also a great year in its own right. The rigor was incredible--we worked harder, by a wide margin, than first-year PhD students--and my fellow students were challenging, engaged, and also quite a lot of fun. The preceptors were (or mine was, anyway) fantastic resources and always eager to help defuse any moments of terrible stress. I really can't say enough good things about the program--the opportunity to work with great professors like Richard Strier and Bob von Hallberg (most profs are excellent about taking time to work with MAPHers and really take your research seriously) and to do high-level graduate work for a year before deciding whether to pursue a PhD is unbeatable, in my opinion. (I did apply to the UC PhD program, not directly to MAPH, but in retrospect I am so glad things worked out like they did. Now I know for sure that the PhD route is right for me.)
If anyone else has any questions about the program, I'd be happy to answer them.