Regulators ranked
Cheap cylinder ones, Male fitting one end, Female the other, TOO RESTRICTIVE
High flow/capacity, Like above but (usually) with a bright plastic grip on the female end.. Too RESTRICTIVE (note change in case)
Camco: (this one has wings) High flow. one RVer I met was satisified but I suspect it's one of the above.
Sur-Flo.. This is the one that is built into many RV's. mine is an in-line, Also restrictive though when it was new.. The word was "Slightly restrictive)
Now I have two 3/4 Inch "Professional" regulators.. one is a Watts, 9 years old, when it was new it worked great, but it needs a rebuild, plus there has been some damage, so instead of rebuilding (I may do that some day) I got a brand new ZURIN.. I ask for either a 1/2 or 3/4 (3/4 was cheaper so I got it)
I set it on 50 PSI Static
I opened the valve on the "Dog shower"
The needle did not even wiggle. IT remained LOCKED on 50 PSI (This is how the Watts acted when new as well)
Valterra makes one for RVers, it is adjustable and has a gauge.. I have not tested it but suspect it will be dang close to the Zurin and Watts.
They do age, and when they get old, one standard rebuild kit helps.