I've got TreadWright's on my FZJ80 right now....70mph+, no problems....the local shop that did the install used to do retreads and the owner was VERY impressed with the quality of the TreadWright tires.
Mine have the walnut shells as part of the rubber mixture and it's noticeable on icy roads. The tread blocks are all the same size, so they DO make more noise than a normal mud-terrain, but I quickly got used to it. I've noticed zero difference between these and my Cepeks as far as handling, and the TreadWrights were impressive in a recent snow run.
They are DOT approved and stamped as such in the re-tread area.
For the price, I'd definitely do them again...mine were done on a BFG-AT carcass.
Heck, my last 'long' run saw 13 mpg on the rig....285's, OME, ARB/winch....not gonna complain on that either.