Don't buy into the Rigid line. I did, and sorely regret it.
A few years ago, I bought a 12v Rigid right angle impact driver, that used a squarish NiCad battery. It's great tool that I've used a lot. A few days ago, I attempted to use it, and found the battery had died. I went to home depot to buy a new battery pack, only to discover that they no longer carry the battery line, non can I find them on their website.
This is an unacceptable problem, especially when I can easily get batteries a few generations back for the Real brands of power tools.
So, I recommend sticking with a main brand, ie, Milwaukee, DeWalt, or Bosch.
Also, the Rigid battery packs are secured with a deeply recessed security screw :/