I used BRS Path 2nd edition to study for my exam last June - I never compared it to the 3rd edition, but I didn't find anything that was outright incorrect. There was 1 spot where I thought it would probably have been updated -- I can't remember exactly what it was, but it was a disease where the molecular mechanism is now known but it wasn't at the time the book was published. Not really a highly tested thing, and I think it was something that was covered in FA and USMLE World. I think the 2nd edition is a very good resource - I would guess that most of the changes for the 3rd edition are minor/cosmetic.