Look at the hot water tank, the valve is right on the tank and the vacuum relief is not piped in a way that allows it to be isolated for service. Also I would have at least 18" of copper of the top of the tank before transitioning to puss-pipe. This is a commercial job. Looks like it was put together by a first year apprentice with no supervision.
I don't mind pex, but this just looks like hackery to me.
The supports for the line to that commercial bibb?
Makes you wonder........