I used Stauns for many years. Seemed fairly accurate though one was very slow and really never closed down completely. Took a while to get them all adjusted, hooking them up to a portable air tank that has a built in gauge and testing again & again till correct.
I always thought they were pretty fast until my friend bought the ARB deflator.
Much quicker to use and you can easily adjust for any condition you want! Haven't used the Stauns since!
I'd used am inexpensive Tsunami compressor I'd won in a raffle several years ago which was surprisingly fast for a cheapo.
When I did ARB locker, I put in Viar Ultra OBA system with 2.5 gal tank, and the thing shuts off at 200psi, so lots more cu ft in the tank.
3 tires filled very fast and have to wait a bit in the 4th.
Quite liking having it on the rig now. I retired the Tsunami to the RZR.