I upgraded yesterday, so far everything is great. I used the method on windows phone hacker, so I didn't loose any data. Overall very easy to do.
mango is so awesome!!
PS during the process I had to restart my computer a few time to get the update to show up in Zune software.
Yep got it running for me, had it going a few days.
Best feature has to be the fact you can't turn the phone off in your pocket!
Little video i made about it myself.
youtube.com/watch?v=eIw8H3sncYs