Robart makes pretty good gear. The only gear from them I hate is the 615 corsair retracts. I used them in my TF gold edition corsair on a reasonably smooth grass runway. Was always bending the links, there are too many set screws that were always loosening up and you had to feather it in pretty good to keep from damaging them. I know, others absolutely love them, I'm not one of them. I will go with wingspan retracts next time I need something.
http://www.wingspanretracts.com/Rotating_Retracts Robarts other retracts are no problem, I've used many of them along with spring-air. But spring-air doesnt do corsair retracts. I'm also using electric retracts in future builds.
Edwin