Sorry to hear about your issues, but it is consistent with the plumbing experiences I have had. Don't get me wrong; I have worked with great plumbers in the past, but right now, locally, I can't seem to find any, well for lack of a better term, talented ones.
I am in the process of converting bad (thin) copper to PEX. I think it is the way to go, especially if you use the Upnor / ProPEX band clamp system, where you get full flow. The only problem is you need a really expensive tool to install it.
Off topic a little: I'm kinda curious. You say your well is 100gpm. Do you actually pump it out at that rate? If so, what do use that much water for?
Don't get me wrong, I'd love to have a 100gpm well.
All the best,
Peter