I don't want to make disparaging comments about software still in development, so this article should not be taken as such. Windows 8 Metro Apps are great. I do not know how well Metro Apps will scale to different display sizes. I am a big fan of Metro. Among all the smartphone operating system, I think Microsoft did the best job of creating an interface that really works well on a small screen.
Microsoft with its Windows Phone OS created an interface that works really well on a 3.7-inch screen. Windows 8 looks like it would do great on a 10.1-inch tablet display. I am not too sure I like it on a larger screen.
One example is the People app which here is displaying my Twitter feed. It displays just three tweets at a time.
The other thing that throws me off is that I realize that on a desktop, I have gotten used to reading information vertically. Windows Phone displays information horizontally.
Windows 8 even its current beta state is fast and stable. The Metro user interface is easy enough to get used too. The area I feel needs most work is the Metro apps. It would be great to use the same apps across multiple platforms, but a changing the way they are displayed on larger screens is not such a bad thing.