I also have the Makita 1/2 impact wrench. The Makita impact wrench was made in Japan though. I used it to remove the crankshaft bolt on my Buick Regal and it did that with ease. I'm not a professional mechanic so I haven't run into bolts that it could not remove ...yet. The only drawback of the Makita impact wrench is that it doesn't have the variable speed control, just full force every time.
As smothers33 said, if you have the drill and impact driver set, it makes sense to get the 1/2 impact wrench as well. It's always cheaper to go with tools in the same system as the batteries are already there.