We have a 6'x12' Carry-On we have been using since '05. No real issues other than a bad ground on a fender mounted clearance light. It has held up pretty well, never had any leaks or broken components. We used it moving the young'n into her new place (multiple trips of about 250 miles each way) and later for moving our household goods from WV to NC (also about 250 miles one way) - probably close to 10K miles so far.
If doing it all over again, I'd look for a more aerodynamic design - like the V nose version. I feel like the sail area of the big, tall, mostly flat, nose adds as much to the fuel consumption as the weight being pulled ... only a few miles per gallons difference between pulling it empty & pulling it with 2K lb. inside. It is as big a trailer as I would be willing to pull without trailer brakes & I generally don't want to pulll it if the weather would make for poor traction (i.e. snow, ice).
Nick