OK, I have done some testing and so far I am not impressed. I have tested only a little bit and only resorted to the instructions that came with it. I don't claim expertice on drill sharpening. I just use a lot off drills. Sales pitch makes it sound like it works straigh out of box and using it does not need any fiddling.
I started with good drills that were only slight battle damage:
* 4,0 mm stub drill (for pop rivets)
* 6,0 mm very traditional drill, but fully ground.
* 6,5 mm drill with larger than normal space for swarf and really easy drilling, needs very little force.
It is not easy to develop good feel with it. Maybe 100 drills later I can produce near acceptable results with it? I geel like it needs a special touch... First drill came out awfully facetted, if held softly the plastic drill holder wibrates in plastic cradle and even when shape looks nearly acceptable it looks horrible under magnifying lense and cuts unevenly.
Yes, it can salvage drills - sort off,
* that sort of geometry is ground that drill cuts metal, but chissel end pushes metal.
* I haven't foud out a usefull way to thin the chissel end. It sort of works, but not really.
* Grinding wheel leaves very coarse finnish
* Plastic parts and weak construction leads vibration/faceting/bad accuracy.
I'm putting here some pictures of the 4 mm drill that I felt was partial success. Compared to original sharpening the drill doctor left it worse on these points:
* needs much more force to push, web is thick, thinning does nothing on this small size
* Coarse finnish, burr, probably edge does not last too long
See picture PC183991_4mm how it should be and rest how it comes out of drill doctor