The update installs from the Microsoft store and will ask for reboot once it downloads and finishes the first part. Then comes the reboot, followed by a few additional ones and takes some time to automatically finish the setup. After your first boot you notice the icon change while booting and a slight chance in the desktop. You still boot to Windows 8 screen rather than a choice to boot to desktop but after going to desktop you discover that the Windows Start button is there.
It is redesigned and it looks nice, but to our shock once you click on it, you land at the Windows 8 boot screen rather than getting some kind of menu. You can get the menu by right clicking the Windows button, which is odd and takes some time getting used to, but at least it gets you quicker to some options. You still don't have a menu or all your installed programs and for them you need to go to Windows 8 start screen and browse or search for it. Not that great.
Search seems more integrated and better and these were two notable chances that we have spotted immediately. Skydrive is integrated much better, but we didn't have time to go in-depth, as we only had a few hours to play around with this preview. We hope to see a better Start button in more mature versions of Windows 8.1, codename Blue.