I have a BoB Yak. Other than this trailer's tendency to get the "Wiggles" at high speeds (Think fast downhills) this thing is a tank! I have used and abused mine for the last 5 years and other than some paint scuffs and a wheel truing (Constant Heavy Loads of 70+Lbs over crappy roads,) it has been Bombproof!
The only change I might make is a better Rim/Spokes/Hub...but again I ask the BoB to do more than the stock wheel is really up to,under most anybody else I don't think this would be any problem.
To avoid the Dreaded "Tail Wagging the Dog/Wiggles" BoB's are known for,load your weight towards the front.