I made a nandroid of my N7 last night and flashed Loly.. This morning by 11am I had restored my 4.4.4 nandroid.
Many of my root apps do not work, others seem unstable. All the Google services work great, I am loving the automatic picture backup of photos and having them almost instantly on either of my devices.
I was really surprised an app like TSTO was having issues, but then again there were probably so many changes to the developer version that most app makers are just waiting for the full release to final and then work on their apps.
Please for the love of god make a backup of your apps with helium, a nandroid with custom recovery if you are rooted, and copy or move pictures, contacts, and what not off your devices before updating!!
If you are rooted and use Titanium, there is an issue with the version of Titanium on the market and all previous versions that will prevent TB from detecting root.
There is a beta version available here that fixes that issue -
https://twitter.com/TitaniumBackup/status/532645824883593216
Happy flashing and updating folks, remember, get your data backed up first.
Edit/add on - Flash at this point is utterly broken in loly.