The problem that I had early on was the fenders kept blowing off and I would call Jim and we would discuss. He made two modifications. The first one helped but did not solve the problem and I told him to forget the fenders. The trailer does not need them but a couple of weeks later he called me and said he was sending me another set to try out. I have put about 2,500 miles on the trailer with the new fenders and they work fine. Jim is always working to improve his line of trailers.
I have several boats. I have carried a 17' sea kayak, 14' solo canoe, 13' whitewater canoe, 10' whitewater inflatable. I have also used it as a shuttle vehicle and carried four boats, it will carry three canoes easily and many combinations. I have mounted a large plastic box on the bed that I carry paddling gear.
As for bouncing around - no this is not a problem. The trailer handles the same with one boat on the side or one on each side. On my trip to AR. I brought up one canoe and one of the other paddlers had a problem with his Mohawk canoe so I brought it back to Orlando for him (their factory is outside Orlando).
As far as other trailers. I researched every other light boat trailer on the market. Reviewed web sites, read msg boards and the trailers that I had some interest in I called and talked to the Mfg. The only one that came close was a bike trailer sold in Calif. that is modified for carrying kayaks.
I believe that Jimco has a bike mount for the trailer. I do not bike so not positive.