As many have said before, it's one great tool. The only thing it lacks before you can start doing some real level editing is terrain, which I know (by the terrain button), will come. I've just one idea for how it might work. Loading height maps and stuff do work, but making a true earth sculptor like to one in earthsculptor (http://www.earthsculptor.com/), would be really really nice.
Because this is the thing editors generally really lacks, a good solid way to mix your terrains, trees, nodes in one solid editor.
Thanks again for creating it. Oscar.