Hey I don't think I ever got higher than a 9 on Princeton's physical sciences sections on the practice exam, but I got a 12 on the 4/24/09 MCAT for Physical sciences. The princeton review is a lot more technical and detail oriented while the actual test was more conceptual...my version of the MCAT was heavily oriented around gen chemistry which was good for me because I abhor physics.
If you are worried that your bad score in physical sciences section will translate to the test...i guess i'm just letting you know that I did 3 points better on the actual MCAT, and it was also a retake..i got a 9 on the actual mcat last september..and this was before i took the princeton course.
i did buy the berkeley review books...and I didn't finish reading them but they do a really good job at explaining things.