Upgraded yesterday on my laptop and I like it. It's quicker, looks nice and feels modern.
The problems I've encountered so far are some of my fn keys on the keyboard are not working, touchpad scrolling within apps and the Start screen doesn't always work and my wifi connection has dropped a few times although that could be coincidental. Hopefully updates will fix those.
Nexus 4: Stock
HTC Desire: OxygenZM 1.2 rom; Bravo Sense hboot; 4Ext Recovery; S-OFF
Sign up for Dropbox and get 2 GB of online storage + an extra 250 MB for both of us, FREE!