I finished my last final on April 25th and began studying for the May 27th MCAT. I actually changed my date from June 17th to May 27th after taking a diagnostic. I used AAMC 3 as my diagnostic and scored a 32 on it. For me content review was true to its meaning, it really was a review. I did well in my classes; thus, I was able to clarify fuzzy points and look over things that I had forgotten fairly quickly.
With that said, during the time I spent doing content review, I studied 12+ hours everyday- 7 days a week.
In terms of what I read for Bio (BR or EK), the answer is both. I didn't review for the sake of finishing a book, but I reviewed untill I can say that I am completely comfortable with the material. For example, on the oogenesis and female sex hormones section, I felt that EK was inadequete, so I not only read BR but also whatever web sources until I competely understood the intricacies.
It is possible to study 12+ a day, 7 days a week, with only nominal study breaks. If you want something bad enough, you will find a way.
Anywho, I will keep you posted on what I scored on the real deal. But to be honest, if I can do it over again, I would have not made the decision to move my exam forward from June 17th. Although mentally I handled the schedule very well, physically it was too draining. I would have used the additional 3 weeks to prep for verbal.
Fingers crossed, hope all the work will pay off. Praying for the best.