Nuru,
It works great, looks like an oversized electric drill, but it takes 1/2" drive sockets instead of bits. It impacts something like 2400 times a minute, so it loosens the nuts for you automatically with no effort. Just pull the trigger until it loosens and spins off the nut. It both loosens and tightens with a forward/reverse trigger. The thing puts out around 250 ft-pounds of torque.
I could not even budge them manually using a long 1/2" breaker bar but this thing spins them off in no time flat.
The DeWalt works like an air impact wrench you would see at a gas station, but instead of compressed air it has an electric motor. It is a lot quieter than the air tools. I did not care to invest in the cost, space and noise of buying a compressor, hoses and compressed air tools. I found it for $175 at Home Depot. Sears Roebuck also has a Craftsman Pro for about the same price, but I went with the DeWalt.