the reg tester definatelly comes in handy if you are regulay stripping guns (nt's esspecially) and re assembling, basicaly lets you tune the reg enough for it to dry fire properly then doing the velocity tuning at a chrono
the best way to use it is to chrono the gun to around 290/300 fps, then test the pressure of the reg and make a note of the reading on the guage, hopefully after that when you set the reg to that pressure then the velocity should be about the same (if the gun has no problems)
so if you tech lots of dye guns and don't have the space or abbility to chrono before you get to the field, then yes
but if you have the option of a chrono then go for that as it will tell you alot more about how your gun is working than a reg tester can
hope this helps
Ryan, team domination