I use Panasonic battery drills they are a bit more money, but they are really powerful and last a long time. I have also owned AEG when they were better, but they are owned by someone else now and not quite so well built, also Metabo they are really good drills, I have never owned a DeWalt they are just nasty. (but their chop saws are good) You won't go wrong with a Makita (another Japanese brand) and of course Bosch another Great drill. There's your answer, buy Japanese or German.
Panasonic for me awesome!