I also have looked into this and a few questions come to my mind:
1: After creation of some additional polygons by extruding polygons, the UVs for that mesh stayed pretty much unchanged.
So, how is unwrapping/texturing done? How can material slots be assigned to new geometry?
2: Pneumatic sound when the tool is activated. I find that highly annoying and distracting.
Can that be deactivated?
3: The lines are a bit too colorful and rainbowy for my taste. Makes it hard to figure out whats going on in complex geometry.
But overall, a definite improvement over the traditional BSP actors 