I'm super excited to have passed the OCPJP 8 Upgrade today with a 91%! Sweet!
I used the OCP Study Guide from Boyarsky and Selikoff along with Enthuware Studio. The book was helpful to get me up to speed and Appendix C was critical with the upgrade exam, focusing on WatchService, FileVisitor, ReentrantLock, and various language enhancements. I would've definitely spent a little bit longer on that. However, Enthuware was clearly needed after going through the book so that I could get a good feel for the upgrade specific practice exam. Unfortunately, the practice exams from the study guide were all for 1Z0-809 so it was a bit misleading for test preparation. Enthuware provided the necessary preparation for me and was clearly worth the investment.
Enthuware Standard Test Results:
Test 1: 61%
Test 2: 63%
Test 3: 66%
Test 4: 72%
Last Day Test: 81%