Just got back from Home Depot as I was pricing black pipe, fittings, and valves for my garage. My compressor is 150 max psi working. The guy at Home Depot said”if it were me, I’d go with PEX”. Flexible, strong, cheaper than black pipe, and you can get everything to fit with fittings as if it were black pipe.
The only thing that concerns me is the PEX looks to be rated at 100psi. Is that a major concern and what about condensation?