As the designer of the sledge I would say this. If your personal 3D abilities are advanced, it is worth the time to build because the sledge is a very capable but advanced 3D plane. Does that make any sense? If not, let me know I will try to answer. The goldberg extra, not my choice. THe EF edge, great plane and I really bounce back and forth between it and the sledge as my favorite. Jeff W.