Thanks to Bob Marino, I had the opportunity to test drive Festool's new TDK drill/drivers which are the follow-on to their TDD product. Available in both a 12v and 15.6v version, the company has produced a great product set that is a step above almost anything else on the market--something that folks will certainly expect from Festool.
Both versions are well made, comfortable in the hand, well-balanced and come in the expected Systainer. As you can see, there are only minor differences in size, most notable in the width of the battery pack on the 15.6v unit. They weigh in at 4.4 and 5 lbs, respectively. In addition to the standard single-hand operation chuck, they both come with Festool's Centrotec chuck for use with drivers and other quick-change accessories. The company claims that this reduces the weight of the drill/drivers by nearly a half pound which should be pleasing when you are driving lots of screws overhead, etc. My only issue with this system is that it will not accept "standard" quick-change driver bits without use of an adapter...they are slightly too big, undoubtely due to metric/inch differences. Festool also offers several other chuck options, including a right angle version and an offset version for getting in close to objects. These all snap on and off merely by pressing a quick release ring. That system works beautifully!
Height-wise, the TDK drill/drivers are about the same as my Dewalt 14.4v XRP as shown here and with the Centrotec chuck in use, the length is noticably shorter. But where you really gain some advantage when working in tight spaces is with drivers inserted directly into the chuck attachment point. Check out the difference here...
Both drills perform as advertised with two speed ranges, forward/reverse switches where you expect them and a very good clutch system to avoid over driving. There is a noticable difference in the torque with the 15.6v version, however...hit the gas and it will twist your hand. The 12v unit was mild in comparison. To that end, if you buy the TDD as a second drill/driver when you have a high power unit already available, by all means the 12v version will be a good choice and will save you $50. For an "only drill/driver" situation or when you know you'll want the extra power, choose the 15.6v tool.
Lastly, these drill/drivers are not inexpensive and you can get a lot of utility out of the more common brands/models available with a lower investment. But I have to say that Festool has kept to their "system" philosophy with these tools and added a huge amount of versatility in the process. For some folks, this will definitely make the investment more comfortable. With multiple, quick-change chuck styles available, compact design and high quality, these Festool drill/drivers are exactly what you'd expect from the company. They get an "all ten fingers" rating from me! (Hello, Santa?....... )