I have used one of these with two travel trailers. Overall I love the design and ease of use with one very important exception. The locking head where it is held on to the shaft can possibly come off on a bump or on a washboard gravel road. The ball bearing nodes that lock into a groove on the shaft of the pin might pop off with enough pressure. The first time it happened a couple of years ago, I did not realize what occurred, thinking it was user error and I had not secured it properly. This seemed unlikely because it is a straightforward design but it was all I could think of. The pin stayed in the receiver but the locking head was gone. From that point forward to now I have always made sure the head was locked securely on the shaft, also testing it by pulling on it.
Then it happened again just recently. This time I was on a rough, washboard, gravel road and suddenly the whole hitch came out of the receiver and the trailer was held up and on only by the safety chains. Fortunately because of the rough road, I was only going 10 to 15 mph and stopped immediately. So far I have not found that any damage appears to have been done, but it could have been a disaster. I was able to get the hitch back in the receiver and secured with a spare pin I carry. Then I got tongue of the TT back on the ball and continued up the road.
Because of my suspicions of how this happened, I will never use this design for a receiver lock again. The old fashioned 5/8" with a pin holding it in seems more secure to me, although it leaves your hitch vulnerable to theft if you don't remove it when not in use.
I believe what happens is that with force of a bump like a speed bump in a campground, or vibration like on a gravel road, the internal mechanism that is holding the locking head on the shaft of the pin can pop out of the groove on the pin shaft. Then the head can vibrate off. Now there is nothing but the weight of the trailer to keep the pin in place. Normally, like the first time it happened to me, that weight is enough to hold the pin in place. But on the washboard road I recently travelled, the constant vibration probably backed the pin out until it fell off and nothing was holding the hitch into the truck's receiver.