i have both for FS9.
they're not quite the same product, and work great together.
Ultimate terrain is for roads, railroads, coastlines, and landclass enhancements.
Ground Environment is a new texture set.
If you can only get one at a time, get UT first, then GE.
Also, adding Flight Environment will finish off your scenery very nicely.
Another thing; You can download Real Environment Pro for free. I used the runway and taxiway textures, along with the reflection and airport lighting enhancements. I think I'm using the trees from it as well.
Go look at this thread:
http://www.simviation.com/cgi-bin/yabb2/YaBB.pl?num=1243393831I posted this in the screenshots forum; its shows the textures I'm using; all of the things I listed above.