The ITPs aren't *that* awful, but do need a bit of massaging to improve their robustness. The biggest problems I had were that the spherical bearings were definitely underspec'ed for this application, the misc. spacer hardware was useless, and the springs supplied with the kit were ridiculously short.
I fixed the first problem by replacing the bearings with a higher grade from Baker Precision. I also upsized them slightly, with the end result being greater than 2X the strength. They were still a lower max load than the bearings that Gary uses. I made my own spacer hardware, and got springs that were more reasonable (8' 500lb on the front, 10' 350lb on the back).
There were other miscellaneous issues: I put hardened washers under the socket-head cap screws on the front (they like to damage the mild steel plate otherwise), and the cut on the threaded collar was abysmal.
In summary, I paid too much for something I could probably put together from a Coleman catalog and a band saw and some welding. But I've been happy with the final result.