I have a LUCAS pistol grip type that I bought at Home Depot a couple of years ago, and carry it in the bed of my company pickup, and it has impressed me for the way it keeps primed. When I was a JD mechanic, and had my farm equipment, I had, and still have a Plews that worked great.
The WORST one I ever had was a Snap on one. (Even my dealer at the time admitted that that model was a joke)