I got my Glowforge more than a week ago now, and I love it. I discovered the 3D engraving capability only a few months ago. It is something I didn’t think about too much, but this mode is amazing. My first 3D engraving projects were two logos that I modified a little for this. I work at the Subaru Telescope on top of Maunakea on the Big Island of Hawai’i, on an instrument called the Subaru Coronagraphic Extreme Adaptive Optics (SCExAO), that takes images of exoplanets. So I had to try our logo and the Subaru Telescope logo! The warping of the wood was a bit unexpected, but probably normal, especially after washing them. Now that they are dry, they are almost flat again. One thing I did notice is that if 100% is white and 0% is black, a 90% level will be the same as 100% on proofgrade material because of the protective layer. So there are little tweaks here and there to improve the result, but I am already very happy with the first try! Here are the results, on location!
EDIT: I like the fact that the engraving naturally darkens the wood with depth. This creates even more volume in the pieces.