Coherence mode will be called Unity mode in VMWare's Fusion when it comes out.
As of now, Unity looks a lot slicker than Coherence mainly because
I didn't see any of that Windows wallpaper show up behind windows when they will manipulated on-screen (except once when one was being de-minimized).
The windows (as mentioned in the videos) have drop shadows which is a neat effect.
These windows act like real Mac OS X videos, so the user can select them individually in Exposé and minimize them individually to the Dock. Heck, this is even more than you can do with Classic on OS X (Classic windows cannot be minimized to the Dock).
I've always found VMWare's Fusion to have a more Mac-native feel than Parallels (native Cocoa widgets, etc.) and that continues to draw me.
VMWare Fusion is promised to have accelerated 3D graphics support in the final version even though their alpha was pretty sad and buggy regarding this and didn't run even Warcraft III.
I absolutely love how Parallels and VMWare are going head-to-head about capturing the Mac virtualization market because they are doing some awesome innovation here.