After using the old style clip on and having a couple go through the prop I switched to the twist lock. Haven't had any go through the prop or fall off. The type with the meter will also help you check your glow plug without taking it out of the engine. They do cost more but they last forever. Most types come with a charger but only need charging after much use. If you have the meter it will tell you when. I agree with the cost factor. Cheap is just as good.