WNAT TO KNOW BEST FITTINGS FOR PLASTIC AIR LINE... PUSH-IN OR COMPRESSION?

Parker all brass fittings I would say are the best but they do come with a fairly large price tag I think I spent like almost $300 locally when I did the explorer a few years back. But I run the numatics nickle plated fittings now on my ranger (the fittings I sell alot of) and they seem to workout great. Eaton also makes some pretty good ones as well as a couple other companys, but I have never had any luck with compression they allways seem to end up leaking.