When we raced the WERA West series, I used a MotoTote (.com) to transport my old R6 to the circuits on the back of my Yukon. The longest haul was to Miller Motorsports Park in Utah, which was 11 hours without a single problem. There was also Las Vegas 2-3 times a season, too.
When we raced the STTARS Supermoto TT series, we used a VersaHaul (.com) double motorcycle carrier to transport two 450's. Combined, the 450's weighed over 500 pounds. If you include the weight of the carrier, it was roughly over 600 pounds of weight on the hitch, and never had a problem.
Trailers are great, but I didn't have enough room in the garage to store one, even the foldable haulers. Besides that, when you're pulling a trailer, you're restricted to whatever the posted speed limit for trailering is. With the carrier, I sped along at the flow of traffic, which was generally about 80-85 mile an hour.
The ONLY downside is, you're basically restricted to arrive-and-race the day of the event, which was a pain in the ass and exhausting, especially with the R6. Meaning, you obviously can't arrive the night before the race and stay at a hotel because someone could roll your bike right off the carrier, BUT how many times have I heard about bikes being stolen from enclosed trailers.
Eventually, we noticed other racers were staying at hotels where the rooms faced and had direct access to the parking lot. They were rolling their bikes into the rooms.
I'd worry about a tie-down strap snapping loose before I'd worry about the carrier failing. Most carriers are extremely reliable, but I'd stick with the high-end units like MotoTote and VersaHaul.
http://www.mototote.com/motorcycle-carriers/mototote-mtx-sport-motorcycle-carrier.html
http://versahaul.com/vh55ro.php