I have used Craftsman, Ryobi, DeWALT and Makita from 7-18 volts. Makita has again produced a tough, handy design. Compared to my old 18 volt DeWALT XRP hammerdrill/driver (which is not balanced and won't stand on its battery) this drill does not pump my forearm like Popeye's after about half an hour. I wish I could say it outperforms the DeWALT in every way, but I expected more torque. Spoiled, I guess. But, the lithium-ion charges last about 1.5 times longer than the 18v nicad in my experience.(XRP was useful to 3/4 hour of #10 deck fasteners) I dig the lithium charging: you can pull it off before the "45 minute" full charge, without lobotomizing your battery. Also cool: The packs HOLD charge phenomenally well; so I can rely on ready stand-by. Ace in the hole.
Bottom line: Light and handy. Short of gasoline fired, you wont find better charge storage, but I find the BDF451 kind of spendy for middling torque.
A couple of other negatives:
1. The light is nice, but it really doesn't point right on the spot you're working on, so it's not as good as it could be.
2. The torque limiting is limited at the low end. In other words, even at the lowest setting, you can still over-drive small screws pretty easily.
3. The switch for changing the speeds gets stuck. You need to spin the motor a little and try a few times sometimes to get it to shift. Not a big deal, but a little annoying.
4. Unlike the drill, the lithium packs are warranted for only 1 year. Standard issue.