I was a firm believer in Bosch tools till I burnt three of them up mixing mortar for my tile in my house. My brother brought over his Hitachi and DANG that sucker is a beast and half price of anything else. I have used the crap out of it where I needed some torque and its in it to win it.
I have the hatachi from Lowes and something in the chuck took a dump after about a year. Took it back to Lowes and had a new one in seconds. It is a beast of a drill for it being so small and light. I'll keep using it until it goes out, then go back and get another. Sometimes they have good sales on them too.
We have found, 1/2'' air drills are the best for notching tube. Most electric drills just can't handle the stress and vibration. I can kill an electric within 6 notches, air drill is still going strong after thousands of notches.