Ok I took the MCAT twice. First time was straight up Princeton Review. Second time was self study with the following materials: Princeton Review Science Review Books, EK Verbal, EK 1001 Chem/Physics, Berkeley Review Practice Tests, AAMC Practice Tests. Needless to say, I've tried a lot of different companies.
First of all, Berkeley Review has far fewer teaching centers than Princeton or Kaplan. That at least partially explains why there are fewer BR people b*tching about their scores. Second, BR doesn't (or didn't) publish materials outside of the course, which also explains why EK has more students b*tching/raving about it in this forum.
That being said, I was told by some people who've taken BR's courses that they work you real hard and prepare you well. Having used their practice tests, I'm inclined to believe those people. Although my scores fluctuated drastically, (especially on verbal which kind of sucked in my opinion), the exam is thorough in its science, and forces you to understand the concepts. It's ironic that something that is tough and detailed forces you to know the concepts, but then again, maybe it's not so ironic after all.
Umm, I guess my point is that BR materials are comparable to other materials. Get as many sources as you can and practice as much as you can. The problem with EK is that people think it's some sort of magic formula. The reality is that strategies only get you so far. At some point you're gonna have to invest in some old fashioned sweat and tears.