I have used the snap on 14 volt, the snap on 18volt, and the millwakuee 18 volt all in 1/2 drive. The millwakuee died first, but in its defense it was abused harder then hard. Fell off a roof once and hardly left a mark. The 14 volt snap on, just died, but only turned out to be the switch. The 18 volt snap on cant be beat. It is bad to the bone. The 14 volt snap on and the 18v millwaukee are neck and neck in power, the the millwaukee is much much heavier, becuase of the brake they have. Remember one thing, that both guns that died were both used daily for the last three years in a yard getting laid down in the dirt, with grease dripping on them all the time. I sent the millwaukee back to get repaired and for 75 bucks it came back working like new. The same for the snap on gun. I just sold my millwaukee so i can upgrade to the snap on 18v. Then once you get the impact, you have to get the snap on cordless drill. That is a great piece also. Got my dad one for xmas, and he cant stop saying how good it is.
In my opionin they are well worth it. No there not as powerful as a good air impact. But they will take off old rusty lug nuts without a problem. If any of those guns dont take a lug nut off, then the nut was way too tight to begin with, unless your dealing with bigger trucks.
Also at the yard we have a maketa(SP) 12 volt impact. Thats a tuff gun. Its been around for at least 5 years and other then having one battery thats gone bad, there are no complaints. Its not nearly as powerful as the 1/2 guns, but for doing small work it just fine.
