The issue I think people are having is that we aren't sure if the ARB/TMJ one is actually made in Australia, or if they just get them from China and put their logo on them. Furthermore, I would conjecture that injection molded parts from China are much the same as those from any other part of the world. Please correct me if I am wrong.
That said, if they ARE made in Australia, then the reason they're expensive is because they're small-run injection molded parts. Injection molds themselves are not cheap. And in order to just break even (what with how much the mold itself must have cost, for a piece of this size), selling only a few hundred of them, they probably need to be about this expensive...
As for an answer to the OP's question, I sincerely doubt there's a lick of difference between the two at all. Both of them are going to be extremely good at what they're meant to do. I say buy whichever one of the two is cheaper.
That said, if they ARE made in Australia, then the reason they're expensive is because they're small-run injection molded parts. Injection molds themselves are not cheap. And in order to just break even (what with how much the mold itself must have cost, for a piece of this size), selling only a few hundred of them, they probably need to be about this expensive...
As for an answer to the OP's question, I sincerely doubt there's a lick of difference between the two at all. Both of them are going to be extremely good at what they're meant to do. I say buy whichever one of the two is cheaper.