My gut reaction is that you're going to pay a lot for a fancy battery may not pay for itself with increased productivity. For some guys the lighter weight and increased battery life will be worth the additional cost.
My limited understanding of the technology is that it’s not quite as simple as taking out the NiCd or NiMH battery cells and replacing them with lithium ion cells. Lithium ion batteries have a different “power curve” than NiCd or NiMH so there’s additional layer of electronics in the battery that essentially shuts off the battery (and obviously the tool) at a certain level of discharge. Which could really suck if you’re 20ft. up on a ladder and two turns short of fully driving a screw. Milwaukee deals with this by adding a “fuel gauge” to the battery pack.
