I have a copper CFC, cooper HEX coil for the HERMS, and now copper plumbing from the HLT. No problems at all! one thing I've been doing is just making sure to run the "stuff" into a bucket when I first turn it on, until wort/clear water flows, then turn it off and attach the QDs. That works well for two reasons- to ensure no verdigris, and to help prime my March pump!
Broken Leg Brewery
Giving beer a leg to stand on since 2006