I just have never seen the need to have a marker knife. To me, they are a gimmick. I just don't think training partners despute contact, even in dueling practice. Even when we do Killshot tourneys, we never seem to need a marker knife to decide who hit who and where.
I understand that sales of these marker knives (from some of the makers) are just not that whopping, so I think many feel that way. A maker sent me samples to sell and it took about 8 months to get rid of 6 of them. Week after week no one bought them, even overseas. Their true value was that they are soft, not markers.
Lots of folks don't like their shirts getting all lipsticked up, too. In a few minutes, the shirts get so marked up, you can't distinguish the last slash from the first. Anyway, these marker knives never interested me. I am not alone and I would suggest anyone thinking about making and selling them should really think twice.
The electric knife is $400? Well, that kills that!
Hock