We use a lot of cordless drills and over the past 2 years have switched over to 100% lithium-ion powered ones with mixed results. Many of the lithium-ion cordless drills have overly touchy protection to keep the battery from catching fire like the million Dell laptop batteries that Sony had to recall. The result is less real power to the motor and slower cutting with repeated starting and stopping.
The DeWalt is the first drill we have used that exhibits none of these problems and that includes the new Milwaukee, Makita, and Hitachi lithium-ion drills we have. The reason in part is the excellent 3-speed gearbox that provides low, medium, and high speed settings so you can match the load on the battery to the job. And it is a true medium speed range of 0-1000 RPM. The Makita and the Ridgid have 3 or even 4 speed ranges but they amount to a low and an ultra low along with a high speed range.
For drilling with small bits the higher the RPM the better in general and having a drill that can run at 1700-2000 RPM is a big advantage. At low RPM's the drill has more torque but with very large hole cutters the low speed setting results in the poorest performance. With a little thought it is easy to understand why faster is better with even a large 6" diameter hole saw. The higher RPM's along with the mass of the hole cutter creates more energy so when the teeth hit a knot or other hard spot there is more mass and force to drive it through smoothly.
We use the new Blue Boar big gullet tungsten carbide hole cutters from Hole Pro and we can use a 6-1/4" size even cutting through 1-1/8" thick Advantech subflooring using the DeWalt DCD970 hammer drill. The low speed setting is OK but it is a bit tricky to maintain control with the lightweight cordless drill, and a lot like using a 2" Lenox One Tooth hole cutter. But at the medium speed setting it cuts like the proverbial hot knife through butter, in half the time and with half the effort to steady the drill. DeWalt's manual for the drill shows 2-1/8" as the biggest hole saw to be used in wood but with a modern hole cutter you can easily use one three times as big.
Battery life is also much greater with a modern big gullet hole cutter than when using a bi-metal hole saw. We get 30-40 times more holes per battery charge using the Blue Boar TCT hole cutters than if we start out the day with new Lenox hole saws. Saves money on spare batteries and we quickly learned that to get the most in performance out of modern cordless drills it is critical to use the right hole cutters as well.
The DeWalt DCD970 has a self-tightening chuck that is unique and really stays tight. It actually requires a short breaking in period to loosen it up a little and until it does (after about 10-15 uses) we needed pliers to loosen it after drilling. When cutting materials where there is a lot of vibration, like boring through stucco and OSB with a Blue Boar TCT Stucco bit, the drill chucks on the Makita, Milwaukee, and Hitachi drills would all tend to loosen up and we need to be re-tighten them half way through the operation. No such problems with the DeWalt drill.
Recharging the full size lithium-ion battery packs is done in 15 minutes and is much faster than we find with the lithium-ion battery packs for the Makita and Milwaukee and Hitachi full size batteries. That may end up shortening their useful life so it is not a given that shorter charging times are necessarily better even though it is frequently proclaimed in the advertising, whether true or not.
The DeWalt DCD970 hammer drill has a second handle that can be tightened in any position in a 360 degree arc. I find it much easier to control the drill in tight quarters when I can have the second handle in a location that is not exactly 90 degrees to the main handle of the drill or even at 180 degrees like is standard for very large stud drills. With the Milwaukee and the Ridgid drills the second handle can only be attached so that it is exactly 90 degrees to the handle of the drill and half the time this is fine and half the time it would be better to have a different position. Makita and Bosch also provide full adjustable second handles for their cordless drills.
The drill is not the best balanced or with the most ergonomic grip but that is a minor quibble. The bearings are not as smooth as the Bosch, and the storage case is downright crude compared to the ones from Milwaukee, or even the ones used by Makita and Bosch which are in the middle of the bunch.
But when I am working on a decking job or boring large holes in wood or masonry the DeWalt DCD970 is the drill I grab. It provides the power and the torque settings I need and the chuck never lets go of the bit. DeWalt was slow to release a lithium-ion powered hammer drill but it was definitely worth the wait.