I try and be on the bleeding edge, I think PEX with proper crimp rings/brass fittings/etc. is the way to plumb. The Sharkbites have always made me wonder, but a failure in any of the places I'd use them (basement) would not be the end of the world, and I've seen new houses with copper pipes which leaked a couple months after the build, PVC drains leak, etc.
I'm working on a new first floor laundry, and I purchased my first CSST and a termination plate for the dryer. I was pretty shocked to find all that seals the CSST to the brass fitting is a single rubber (actually I'm sure a composite with nitrile/etc, perhaps zero natural rubber at all) washer. Makes me wonder - are we living life on the edge with these washers, or is their material just above and beyond what we think of when we think of your typical washer?
Code tends to live far beyond the bleeding edge in the eye of safety, and while there was a big push for PEX acceptance once copper got so high, there was no big reason to leave black iron pipe other than installation convenience, which I'm all for. (Yes, there were reasons to switch, but not a huge push.) Are we being too careful?
I'm sure at some point, having running water in your house was asking for a leak, and having explosive gas piped through all the rooms of your house probably seemed like a HUGE risk for the early pioneers
