RE: Hitec Karbonite
They have outstanding precision and absolutely NO slop. As for breaking them, I did not break any and I have 3 of them (5975) on my 1/4 scale cap 232 which weights 11 lbs and is powered with a YS 140 DZ that is far from being a very smooth runner as it is hard mounted. I have about 100 flights on 2 of these servos and they do not show ANY sign of wear so far. The third one was added last week.
2 of the 5975 are on the elevators and one on the rudder. I had last year 2 5925 on the elevators and removed them to save some weight in the tail of the plane in favor of the 5975s. This to say that I have about 100 flights on each set of servos and I can say that they all hold up pretty well but the metal gears have a tiny amount of slop (maybe the same amount of slop as a brand new servo).
The Hitec rep says that one should not put a single servo in a plane larger than 12 lbs. It seems a rather small plane but when you consider that big guys put 4 servos on the rudder of their 40 lbs airplane or 10 lbs per sorvo, the 12 lbs limit seems well within reason.