Yeah, I basically scored the test number, so I didn't miss it by much. I found so much overlap between 680 and 686, that I just decided to take it without much additional study, so I'll be using my 2nd shot soon.
I want to word this very vaguely, so as to not violate NDA, but I noticed that I had several questions on MED-V, which was not covered in any of the prep material I have. I used the Gibson book and the MS Press book (although I admittedly didn't go through them as thoroughly as I have done in previous exam preps). In any case, after the exam I looked through my material and MED-V wasn't even mentioned, let alone covered in depth, in either of these resources.
That said, after some hunting around, I found this as a starting point for the topic:
Technical Reference
My questions may have just been the ungraded trial questions, but I thought I would post this here as food for though for anyone taking this exam any time soon. My worst area on the test was Designing Application Packages for Deployment, which I have since remedied. There were a few things I was weak on, details wise, which the test accurately and fairly exposed when I took it. The test didn't feel cheap; I simply took it too lightly the first attempt. That won't happen again.
Retake is tentatively scheduled for Tuesday, so we'll see how round 2 goes. I'm cautiously optimistic, which means I'll probably score in the low 300's. I'll update this either way, afterwards.