For a long time I was skeptical about battery powered tools. I had bad experiences with nickel cadmium tools many years ago, but everyone tells me that lithium ion batteries are much better. I wanted a cordless impact wrench to get suspension parts from a U-Pull junkyard and cheap parts would basically pay for the tool with one use, so I got it. God I'm so glad I bought this instrument! It easily removes rusty screws that my air screwdriver can't remove. I've found myself using it a lot more than I expected. It's so easy to pull out and use for a screw or two that it's not worth running the compressor for the air wrench. Battery life is impressive - after removing the wheels from two cars (40 nuts total) the battery indicator still shows almost full, and it's fully charged in just 5 or 10 minutes on the charger. It also holds a charge well, works great after a few weeks on the shelf. The only downside is that this tool is heavy and quite bulky.