I have had 2 different cars with Jess's axles, both V-8s. I have not had a single problem with either car and I drive the p!$$ out of this new one and it's powered with a built LS2 by CBM.
I think if you take a look, you will see in the previous threads and EVEN IN THIS THREAD, that most of the guys that are NOT having problems own Desert Dynamics or Buggyworks (same frame builder) cars . They seem to work with DD's geometry/design.
I also thinks it has a lot to do with the frame. I'm not saying one frame is weaker than another, just that they seem to work fine on DD cars regardless of HP. I, like John, ^^ run with a BUNCH of DD/Buggyworks cars who all run Jess's axles and none of them have had the failures mentioned in all the previous threads.
My next car will also have Jess's axles and it will be a DD frame. It's a good combo.