A week ago, in a follow-up to Doc Holliday's post about Rigid brushless drills, I allowed as how, in my price/performance range, my research had put Milwaukee at the top of the list of brushless 18v drill motors, with Hitachi, Makita and Bosch pretty much equally in 2nd place. The Milwaukee, while clearly the leader in torque, run time and speed, was also far-and-away the most expensive. It was also the heaviest. The Bosch came with 2AH batteries, rather than 3AH. So, for me, it was down to Makita vs. Hitachi.
Makita has always been one of my favourites, but I'd always wanted to try a Hitachi power tool. So now it was down to "which felt best in my hands." That ended-up being the Hitachi 18-Volt Lithium Ion Hammerdrill and Impact Driver Brushless Cordless Combo Kit, Model #: KC18DBFL, carried by Lowe's.
As an aside: A funny thing happened while I was on my way to the cordless drill purchase: I "discovered" impact drivers. Like many others: I always kind of figured that, where driving screws was concerned, impact drivers were kind of gimmicky. But after reading what others had to say, I was willing to be persuaded that perhaps I'd been wrong. So now my purchase would be a drill/driver combo kit.
As I mentioned in another post to DH's thread: I had an immediate project: We're putting up a new 12'x16' shed. The foundation will be 6" of packed crushed stone, retained by 6"x9" creosoted railroad ties. I wanted to make certain those RR ties would stay put. To that end I would drive 14 each of 18" long pieces of rebar through them; fasten the corners with angle brackets, using 6 each 5/16"x3" lag bolts, and tie the "butt splices" with straps using 6 each of the same lag bolts. I knew there was no way my ten-year-old Makita 12v cordless drill motor was going to handle all that. Besides: Every new project demands a new tool, right?
Cutting to the chase: Friday afternoon the new Hitachi drill motor drilled 14 each 1/2" x 9" holes in those railroad ties (in speed range I), using a twist bit, and never missed a beat. It was going as strong on hole #14 as it had been on #1. Each hole took about 70 seconds to drill. The impact driver drove those 5/16"x3" lag bolts 56 times (each bracket had one bolt driven twice) and, likewise, never missed a beat. Neither tool required a recharge.
I would note the lag bolt holes were pre-drilled with 1/4" bits, with the shank areas relieved with a 5/16" bit, using a separate set of cordless drill motors.
Friday, the last set of four 1/2" by 9" rebar holes were drilled all in one go. Yesterday the six 1/2" by 6" holes I had to drill were done in one go. In neither case did the drill motor get warm, much less hot.
As for the utility of the impact driver? I'm a convert. I was able to effortlessly drive those lag bolts regardless of how I held that driver.
N.B.: Always wear safety glasses when using an impact driver! I occasionally had tiny metal chips hit my face while using mine. (Personally: I've gotten into the habit of always donning safety glasses when using any power tool or wielding any hand tool that involves even the remote chance of something going flying.) Also: Make sure to use impact-rated bits and sockets. Bits/sockets designed for manual handles, or even suitable for regular drill motors, can shatter under the force exerted by an impact driver.