4.9.1 is out as of yesterday also if you are on 4.8.2 or higher and do not have your compliance module auto upgrade they have released the 3.5.771.2 compliance module as a manual update.
They appear to have fixed most of the bugs I reported such as support for Windows Phone 7.X, Blackberry Support, fixed the unknown user issue, IOS devices not loging in correctly (there is a 4.9 patch for this also) and some common schema upgrade failure issues. I will wait for some people to report back as I hope this is not the train wreck 4.9.0 was.
