From a personal point of view, I really do like the use of PhysX for the physics side of things, but other than that, I think that 3D Rad is far more intuitive and simpler to use, as well as living up to its RAD part.
In the near future, as a personal exercise,I would like to port the three major Unity tutorials (3D Platformer, FPS, and 2D Platformer) to 3D Rad for comparison purposes.
My Eureka! project is progressing well.......no major hiccups. Just waiting for the November update for a fix on the Buoy Object bug.
Meanwhile, here is a video of the Spring Balance in operation.