I had the barbri book and the "Supreme Bar Review MPRE Review" book. I read through the outlines once and then did all of the practice tests. I think it probably took me between 10 and 20 hours total. I wasn't happy with my scores on the practice tests, and I felt like crap after I took the test. I got a 107.
(To give you a gauge of my abilities, I got between a 158 and 162 on the LSAT)