I too saw (and fondled) the KMP retracts at the Toledo show, and they DO look very promising. Struts appear to be 3/16", which is just right for these warbirds. I inquired as to whether they are available seperately (from the Corsair ARF that they sell), and was informed that they are not at this time. When/ if they do become available, then Robart and CJ will have some SERIOUS competition, and we may have a winner in rotating retracts.
Yes, Robart should be ashamed, but so should CJ. One thing about the Robarts that I consider a plus: they actually have 100 deg. of retraction, which allows the installer to mount with some forward 'rake', which in turn allows the RoboStruts (if so equipped) to function better. They also are easier to fit/ install into the wing than the CJs, and have a lower overall profile. And then there are those CJ struts, they are just plain ugly and cheap looking, especially compared to RoboStruts. The CJs just may hold up better to hard landings, but all factors considered, I still favor the Robarts over CJ.
The old (discontinued) Rhom-Air retracts are a good alternative to Robart and CJ. Simular in design to the KMPs, and available with 3/16" struts. I have had good success with the Hobbico mechanical rotating retracts, BUT I use them in a 5 1/2 lb DynaFlight FunScale Corsair, and would not consider using them in anything heavier.
One more thing about the Robarts: many have encountered problems with the struts rotating when they are not supposed to (including myself). I consider this to be a builder issue (as in MY fault), as it is usually due to insufficient number of set screws and/ or failing to grind small flat spots for them to anchor onto and/ or not tightened enough. I now install 4 , 6x32 set screws into each RoobStrut, and enlarge the gear tooth set screws to 6 x 32, and use button head or regular allen head screws when possible (easier to apply more torque on button head and allen head than regular set screws). With that done, my unwanted rotating problems went away.