I have the newer
Drill Doctor 750X it has some improvements over the original- holds the bits better, etc. It will also grind standard tips to a split point (they wander less). I have a full (150 bit?) cheap (China) drill index that I got for XMAS one year. These bits, even the almost never used ones, work much better after one sharpening with the DD! It is going for around $120 now from most vendors, and will pay for itself with the time and money you save not driving to the store and buying a new bit. You really save if you are sharpening masonry bits! One caution, if you don't use the depth stop or are not careful tightening the bit in the chuck, you can really take off some metal and end up with a bunch of stubby little bits! It may initially seem awkward to set up and use- practice on some 'throw-away' bits first. After sharpening one or two bits it will be second nature and is really quick. I jump back and forth between drilling wood and metal and it is so nice having sharp bits!