I was lucky enough to have attended the Microsoft Build conference in Anaheim CA last week and as an attendee received a Samsung Slate PC tablet that was pre-loaded with the Windows 8 Developer Preview. I have been using it since I got it last week and have found a few issues.
First, I chose to setup the machine by using my LiveID account instead of creating a local user. My LiveID has a "_" character in it. When I tried to compile one of the stock Visual Studio WinRT based app template apps out of VIsual Studio the build worked fine but it failed to deploy. After closely examining the error message I quickly realized that the problem was that Visual Studio was replacing the "_" in my userID with "." character. But on disk the folder did contain a "_" character so Visual Studio was basically trying to deploy to a folder that doesn't exist. I filed a bug with Microsoft using Connect but I also realized that the immediate solution would be to reset the machine using the new Windows Reset feature and create a local account with no "special" characters in it. I did this and then linked up my account with my LiveID and all worked well.
Second, many of the apps that came preloaded on my tablet would not run. When I tried to launch Tweet@rama or a few of the other apps they simply would sit on the splash screen or with a loading spinner. After some digging I found that I was able to fix all of these errors by navigating to C:\Users\scullinan\AppData\Local\Packages and finding the folder for the app I was trying to run. Generally the name of the app was at right after the manufacturer name (e.g. microsoft.tweetrama.*), in the case of the "news" app though the name used was "hermes" for some reason. Inside the folder for the app I was having a problem with there was a settings.dat file. I deleted the settings.dat file, relaunched the app in question and voila, it launched successfully. Oh and if you get an error when trying to delete settings.dat simply run task manager and kill the app. Also you may have to click "view->hidden items" on the Windows Explorer ribbon to be able to navigate to the Packages directory.
I hope this helps. This is obviously very early hardware and software and there is much for Microsoft to do. It looks interesting though and I plan to summarize some of what I learned at Build, post tutorials on how to convert some of my .NET code to WinRT, and review the hardware provided to us at the show.