It features a new start screen, and the more familiar desktop screen somewhat secondary. I don't have a touch-screen based interface, so bare in mind that this was used with a keyboard and mouse. Since the aspect ratio is 5:4, with a resolution of 1280*1024, certain features like snap to the side of the screen are unavailable.
To access all programs here, press the WinKey and C. To have those black boxes at the bottom of the above screenshot to appear, just hover the mouse at the bottom left. Option to shut down, sleep, restart, etc., are in there too. Wifi could be selected either in the settings menu here, or the taskbar of the desktop.
This is the weather app. Depending on your screen resolution, you can see only part of it, or the whole thing plus other cities you added. The background image is animated, which is based on the current weather and the time of the day. I don't know how to adjust the settings, but the date/time is in Japanese format, the temperature is in degrees Fahrenheit, and wind is in mph.
Next is the Twitter app that it comes with. I don't see where the settings are, and clicking on a username will bring up the user profile on the Twitter website via Internet Explorer instead of the app itself. CJK characters don't seem to be rendered smoothly. For some reason, when I tweet from this app, the tweet went through, but doesn't update here. (I knew the tweet was successful via another device.) Another oddness is that my timeline is blank, though when I sign in with my other twitter account (below image), it appears fine. I don't know what the problem is.
(Parts of this image is censored out to protect privacy)
Next up is another social app, but for Facebook. It features feeds from friends, your photos, profile, and the Foursquare-like thing called Places. The interface looks like it could be improved further. In the photos section, any images that are not of 1:1 aspect ratio have ugly black bars surrounding it, especially vertical images (not shown). The image thumbnails were simply resized instead of cropping it.
I would like to try out other applications, but the app store isn't open yet. The apps that it already comes with seemed to be specifically designed for touch interface. They work with keyboard and mouse, but I don't feel comfortable using those with those apps.
Overall, Microsoft has done some great effort in radically changing the user interface that has not been seen since Windows 95 with an interface called Metro. Metro is based on the (now discontinued) Zune player interface and has been applied to UIs, such as Windows Phone 7 and Xbox Dashboard. However, I have to say that it's confusing to people who have been used to the older interface. I know a lot of companies that still run Windows XP with the classic interface (Win2k/ME/98-like) today. Then again, I don't want to see a visibly old interface that is still being used a decade later.