[ToddF]

Nowdays, any major manufacturer (there are about 5) is going to make good powerful drills that hold a charge for a reasonable amount of time. To differentiate, you need to look at the failure modes which are most likely to effect you.

For me, in my personal shop, I take very good care of my tools. Over the years, I have ended up with several cordless drills which were physically perfectly fine except the batteries no longer would hold a charge. What good is a wonderful high quality drill with a dead battery which costs 75% of the cost of a new drill to replace? I did research and found that the only major manufacturer with a lifetime guarantee on batteries is Rigid. What that means is that if a battery dies for any reason, you get a free replacement.

Now, for our robotics team, the most common failure mode of our cordless drills is for a drill to be sitting on a workbench and someone to bump it off onto the floor. The drill flips in the air and lands on the chuck, bending the shaft that the chuck threads onto. At this point, I think we have four cordless drills (all dewalt) and at least three of them have wobbly chucks from bent arbor shafts. For students who are struggling to develop their hand drilling skills anyway, a wobbly drill is just worthless. To date, I haven't identified a suitable solution to this problem. There are three approaches I'm thinking of taking:
1) Buy a drill with a larger, stronger arbor shaft. (Probably would also mean the drill is bigger and heavier. Not a good thing.)
2) Buy a lighter drill with less of a probability of bending the shaft when it falls off a table.
3) Buy one of the newer "pistol style" drills which, since they have no wide battery base, don't sit upright on the table. and are less likely to land on the chuck if knocked off. These also tend to be smaller, lighter and cheaper, all plusses for students with smaller than adult man hands.

And now that I've thought it through, I think we'll be buying a couple of the Rigid pistol style drills in the near future.