I realize this is too late for echo but might be useful for a later patch / version.
The groups are wonderful but when you go into the material editor it's impossible [unless I missed something] to edit the materials within a specific group.
Also, I think that when browsing for materials it should display thumbnails. Otherwise I always have to have a separate image viewing program just to see what I'm opening.
Lastly, could you add a modifier key to the scale / move gizmo to have it go incrementally? For example, if you hold down control while scaling it locks into 10% increments in size of the original. Or moves by .1 KT-unit.
These are the biggest requests I have for now... other than that, this new version is very exciting!
XP SP2, Core 2 duo @ 2.13GHz, 2 GB ram --