Its very good, but its not exactly user friendly in someplaces - seems rather "clunky". I am currently working on a GUI that includes buttons, windows, listboxes, scroll bars, menu bar etc., and takes little FPS (on mine between 5-20). I would be willing to donate it to this project.
Could it be possible for you to release both the code of the editor, and something to test the map in, e.g. some little platformer.
This is a good editor and should do well
RED GENERAL
My computer melts regulary - perhaps it likes being fondue