i have the dewalt at home and if you manage the batteries they will last reasonably. the impact itself is great, excellent for lugnuts. kinda hard breaking ubolts loose. easy cheesy for spring bolts and assembling 205s.
the snap on i have for work is awesome! batteries last a good while and they dont go down steadily, just up and die at the end. strong enough for super duty lugnuts, it does nearly everything i need.
the only complaint is that its a little heavy after using it all day.