@nawrp11 - I think The Berekley Review (TBR) is a great MCAT prep company. I like the people that run the company and think they're as committed to seeing their students succeed as any company out there. Their science material is the best there is. In regards to the CARS, I'm not sure it's your best bet.
After removing the natural science passages, their verbal book (
Berkeley Review's Guide to MCAT Verbal - published in 2013 and to my knowledge has not yet been updated for the "new" MCAT) has 69 usable passages. (This is because the natural science passages of the old verbal section no longer are pertinent for CARS preparation.) In terms of quality, I think their verbal passages are not as strong as other materials out there. They were good, but I would rate them behind TPR and EK. I did a number of practice tests worth of their passages but found many of their questions to be too detail focused and that they didn't correspond all that well to the CARS. I think they'd be useful if you are doing a long-term study plan where you’ll be doing passages 6 months out from test day. Also, the book costs $70 dollars new, so you’ll be paying roughly $1 per passage.
I think people don't use "them" because one only has a limited amount of time to prepare for the MCAT and it's a major waste to spend time taking and reviewing a practice test that doesn't resemble the MCAT CARS all that well. You probably won't see much of an improvement using their materials save for getting your timing down, but it's just silly to use sub-par materials when there are cheaper and better options out there.
Best of luck!