I've often thought one of the reasons for Terragen's great terrain resolution had to do with it's 16-bit terrain rendering. Vue 6 announced such support but it took me awhile to figure out how best to use it. Below are the results of my tests. It appears 16-bits really help terrain resolution significantly. More tests to do..

If you haven't yet seen my Step-by-Step tutorials on terrains and mapping you might gander over to:
http://www.altuit.com/webs/altuit2/VueStepbyStep/default.htm at your convenience.