This is a great addition to 3DGS.
It works very well already on my system and I can see how this is going to make creating levels a lot easier.

Support of dynamic light would make a huge difference though.
Because I think lighting a level is one of the most annoying things at the moment but also one of the most important ones to get the atmosphere right.

One problem I came across so far:
Some objects would face the wrong way after I've saved the level in GED, then moved back to WED and did the reload. So there was a difference between what I did in GED and what got over to WED. Compiling in WED then also removed the change in the .wmb