Check the forums on facebook, they have started working on the differences between 2015 and 2016 and a pdf is up there.
There are definitely some changes in FA 2016, but they are quite minimal. I have compared every section pretty thoroughly, except for Reproductive. There are no more than 10 new disease additions (e.g. Nelson syndrome, intestinal atresia specifications, hemolytic uremic syndrome was added to the platelet disorders section in Hematology, ABO HDN, Hyperaldosteronism, scabies, etc.). There is also a new Respiratory Embryology section, there is a clean and updated version of acute MI complications, and there are new drugs and diagrams in the Pharmacology sections.
I personally find the newly-added diagrams throughout the new edition to be usefully updated and worth taking a look at, but if you already knew the information as it was presented in FA 2015 then what you will come across in the new diagrams in FA 2016 are merely a more organized way of seeing what you already know.
Overall, the changes were enough for me to transfer the missing information, the new diseases, and some of the updated diagrams into my previously-annotated FA 2015 (I annotate electronically). Having said that, I don't think it would make a true difference for anyone who decides to stick with the 2015 edition for an early 2016 exam, as long as they are covering the missing information in UWorld or another resource. It is also worth noting that, contrary to what I keep seeing on numerous message boards, there are
very few new histopathology image additions; in fact, some of the FA 2015 images were shrunken in size, or were even completely removed. In
most cases, I actually preferred the FA 2015 images and kept a lot of them instead of switching them with the new ones from FA 2016. Hope this helps.
