Hi I have only built one Staton. They are a bit pricey, BUT I do LOVE the fact that the gearbox is American made!
I found the box to be well-made, tho very heavy. I could not imagine that it would fail. The instructions, tho, were of a type, where failure would be an easy thing to imagine, BUT, Dave was reachable by telephone, and tho we were breif in the conversation, answered all questions I had about the peculiarities of the recumbent 3-wheeler that I was building.
The box was not silent, BUT, was very acceptable noise-wise. The customer had provided a gx35 Honda for this build, along with a gx50 for another build. I was amazed that the honda pulled me well in the trike (I am a heavy rider).
I had experiance with 2 RS 35's they were smooth, quiet, but I felt underpowered, BUT, they were brand new, and not broken-in, where they could gain power.
I had one of this with the exception that it was inside drive. It was a hard to set up kit but all kits take some care to get right and are worth the effort. I put on about 1500 miles and loved the kit. I sold some of the parts and am using the HT for now but may build another Staton. The cost is not just easy money for Staton as he does a lot of machining on a very well built gear box. You can go lighter but not more durable. A misconception is the higher center of gravity being a problem. I mounted mine very sturdy to keep shifting down and the balance was great.