As a gnome I got to use the ultra-vision last night.
To give you an idea of what it is like, take the regular image, switch it to high contrast grey tones, and then instead of black and white, use shades of purple.
it makes for a rather surreal view, but has the advantages of making edges and such (like the begining or end of terain features) stand out greatly.
The down side is that creatures and finer detail tend to blend in to the background a bit. The saving grace of this is when a creature moves. When in motion they really do stand out quite nicely (although, I doubt as well as a race with motion sense).
I used it a lot.