I use the better of the CSV's on my 3-stage, 2HP Goulds shallow well jet pump. Mounted right on the pump's outlet.
I have 6 shower heads (2 stations) in my 9 foot by 4.5 foot shower, an 80 gal hybrid water heater.
I hated that when using just one side of the shower, the water pressure would cycle from 65 to 95PSI, up and down. But was steady with the wife using the other station at the same time. So I installed the Stainless CSV and a small pressure tank instead of the huge one.
Works wonderfully. AS LONG AS I have it set correctly. It is easy to set it to prevent cycling under all conditions, but that just runs the pump too much. So I set the CSV to prevent pump cycling when using one shower.
There are many CSV detractors, I am not one of them. I find it to be an ideal solution for my high pressure, high flow requirements.
CSV1A is the one I have:
Note: I purchased just the valve, and did not purchase a kit. I use a relatively small expansion tank, about 7 gals of draw down. The tank is the $200 model from Lowes.