So, I'm looking at a cordless impact driver (
Makita 6932FDWDE.)  I like that its very light, and has great torque.  Has anyone used an impact driver?  How do they compare to standard cordless drills?
Also, I don't need to use it as a basic screwdriver.  I have a 
DeWalt DW920K-2 for that.  I'm going to use a drill for installing plasma panels and projectors, while hanging off of a ladder.