I indeed have some troubles getting the 16.08 (KDE minimal, testing) release to work reliable with my NVIDIA GTX770. I am currently updating again, since I saw there’s a new driver in these updates. I just hope it makes it until the end. I downloaded the ISO a few days earlier so it is not the just announced build.
P.S. Maybe it wasn’t related to the gfx card but the recent gtk issues. The hangs occurred e.g. when using qupzilla. I guess one could wait until there are more experiences coming in. I also remember I tried Nouveau drivers and it was worse.
P.S. just to update, I did a re-install and did the upgrade right after. No issues so far, everything running smoothly. I only had the issue with my live system (before install) and with the system prior upgrade.