I can't help ya much. I use Autozone vert mounts on my fox (made in India) and they seem to have done fine. Tom Moss runs or ran the same mounts on his fox. They're lifetime warranty and pretty easy to swap out.
I'd maybe call around and ask for brands (or countries of orgin in cases of repackaging). That said, I'd consider going with poly if the cons are acceptable. They should hold up quite well.
If you want to compare ES and Prothane, there was a 5.0 Tech thread started by Kumm (I think that's the right username. Maybe it was Kumm3) where he had pics and dimensions of both.