Update was finished without any problems and after 3-4 hours I saw my new desktop. I'm rather a user who keeps opened a lot of windows simultanusely and for me the most important new feature is the support of multiple desktops:
I was using this in my Gnome desktop for a long time and one thing what is missing for me in the Windows implementation is a possibility to move window between desktops using a shortcut (or I missed this in the shortcut list). Nevertheless, the work on Windows isn't as much painful for me finally.
I also noticed one regression in sense of usability. Developers changed power management popup (shown after click on the battery tray icon) and now it is less functional:
I often switch between balanced and high performance modes, but now I can turn on/off only power-saving mode. To run high performance mode I have to click few times more (open power settings). This is the reason why I created shortcut on my desktop switching to the high performance mode:
powercfg.exe /setactive GUID
Where GUID is one from the list: