Ive been doing plumbing work since I renovated the family bathroom in 1978. I watched plumbers solder when I was a kid and was fascinated by it, I learned how and it was super easy, joint has to be super clean by abrasion and well fluxed, no problems. In multiple buildings ive plumbed over the years Ive never had 1 joint failure. My buddy's house had poly b and hes had leaks everywhere, as we know now, it was complete shit. So I dont trust any plastic.
I remember the Texaco gas and garage where my dad had the car fixed, It had copper lines for the air. So that must have been good.
My current place, the compressor, A Devilbis 10hp. 3 phase is in a compressor room 8x8 with concrete block walls and a vent for air draw and cooling The main lines out are 1-1/4 galv steel and they go under the slab to several risers and a line goes about 100ft to building #2.
Outside anything exposed is galvanized, anything inside is black iron, painted blue.
Ive plumbed 1000's of ft of iron pipe in mills when I worked in them
Ive seen some backyard guys around use white PVC farm irrigation pipe, if sch. 40 is used, primed and glued properly its good for 160 psi water.
Ive installed 1000's of ft. Of PVC on various farms, so theres another option.
Each outlet has a T, a 6" drop leg with a small drain valve for garbage and condensation and a horizontal nipple with1 1/2" valve before the quick fitting. I dont leave any hoses plugged in overnight.
For me, anything other than iron pipe for air lines is not a consideration at all, IDK about the new plastic but it has to be rated for at least 160psi.
If one wants to keep the compressor off at night could use a good timer, GE or square D and a relay if 3 phase
So theres my .02 (..1.45 USD)
Hope this is any help to others