I have tried em all, the dremel tool thing really didnt work for me. Unless you saw the stone back and forth as you sharpen, the stone wears uneven.
then to make matters worse, as the stone wears down the diameter becomes smaller and you get some weird looking tooth edges, not to mention the tooth profile then becomes something that works against filing by hand.
Nope, finally settled on filing by hand, and taking the chain to the cheapo grinder from NT if the angles get off or it gets rocked out.
Best hundred bucks I have spent in awhile. I reckon there must me at least a dozen posts on this subject, including a post where someone on her figured out a way to make some shims to take the little bit of looseness out the rig.