Well... with the release of Unity 5.8 and associated dependencies, we got the extra testing we were after in precise, and with it a number of bugs. The positive side to this is that with the extra information from our wonderful beta-testers we have been able to work out how to reproduce a number of the issues. As any developer would tell you, being able to reproduce your user's problems is often the biggest hurdle.
Over the weekend I noticed a number of issues around the release of Unity 5.8, and this morning while going through the bug reports, I was happy to notice that we had some way to work around most of them.
Unity 5.8: Flickering and corruption on Unity UI elements - a fix for many is "unity --reset". The cause appears to be how compiz is dealing with plug-ins that are no longer around. For some there have been plug-ins that existed with Oneiric that are no longer around in Precise, and the reset caused them to be removed from the list to load.
Unity 5.8: Login to blank screen (all black or just wallpaper) - some have been fixed by "unity --reset", but the underlying cause of this one is still a bit of a mystery.
Unity 5.8: Can't login to Unity since upgrade to 5.8 - some have found that disabling "Unity MT Grab Handles" compiz plug-in fixes this issue. We still need to work out what the underlying problem is.
white box randomly shows up at top left corner blocking applications from using stuff under it - this one appears to be triggered by chromium desktop notifications. There have been reports that disabling the animations plug-in in compiz, and then re-enabling it fixes this. We are still investigating why.
If you are getting these issues, you can try the workarounds suggested here.