Krusty... are you volunteering to help out with building terrains...?
I tried 4 or 5 times over the years and gave up every time. It's worse than shell scripting in unix. It's very user unfriendly, not very intuitive, and as such "no" I'm not volunteering to help.
Now, if they had better tools...??
(P.S. I used Hammer Editor for Half-Life for YEARS but when they came out with HL2's editor I stopped because the interface and the way it worked, while more capable, was like shooting your hand off then trying to sign your name with the stump you have left. There's something to be said for well designed tools, and the TE interface... ain't.)