On the other hand, it's not guaranteed that any particular feature you see will make it to the release build - meaning it's easy to get excited over something that may never see the light of day.
Longhorn is definitely a mix of both - applications work well once you've enabled "XP/2K compatability" mode, and beyond the random explorer.exe crash (it's a .NET managed code app, the first such shell in Windows) I didn't have trouble with any other programs.
The new user-interface is particularly appealing; while I was dissapointed at not seeing the 3D UI first hand, the current 2D version they've implemented (Slate?) is actually better than the one I've got on my WindowsXP box.
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