I agree...distance stuff it's passable sometimes, but not up front with close up camera movements.
If you haven't checked out Eric Hanson's dvd's at Gnomon...check em out. It's amazing stuff. Sure it's a little more complex than the create it yourself terrain but the results are great and it could apply to modifying the terrain to meet one's particular needs. The results are alot better for film work than procedural textured terrain.
I'm open to any tools available to get the job done...as long as the result is amazing and believable. And the terrain generators have a looong way to go.