Impact wrench suggestions?

I have an older Porter Cable that I picked up at a pawn shop and it really surprised me how much power it has. I don't know the rating on it cause the tag is worn beyond readability but it has taken stuff off that was torqued to 150 lbs with ease. The 1 drawback is it's corded, but an electric cord is easier to drag around than an air hose so it's not all bad. Another good thing is I never have to worry about the battery going dead while I'm in the middle of something.