I've been having difficulty deciding whether I should buy the new Mcat prep book for 2015, because last year I bought the old Mcat review book. Will be the ocher, genchem, physics and biology be the same? So I can just buy the biochem, psychology, and verbal reasoning and critical thinking book.
Good question! I think this is going to depend on how organized you feel.
Here is the official AAMC PDF of 2015 content: https://www.aamc.org/students/download/377882/data/mcat2015-content.pdf.
You could cross-reference the outline of topics with your current review books. The science itself may not have changed, but the new books are going to follow the 2015 breakdown.
Consider buying a all-in-one review book that covers everything, or sit down and annotate the AAMC PDF with chapters/sections matching your books.
Either way, study hard! Best wishes!