I had the opportunity to try one. Generally speaking, I tend to hate and abhor coping saws and fret saws and jewelers saws; I don't like having to constantly fiddle with adjusting blades and tightening blades and replacing blades. It often seems that the focus becomes "operating the saw" instead of "using the saw to make what I want."
The Knew Concepts saw was noticeably different, because the darn thing worked--and worked well. You know all those skills you developed trying to get a jewelers saw to do what you want? They make operating a KC saw easy. Out of the box, it was better than any of the saws I've spent time tuning and refining to get something that would work.
I want one. I will have one eventually, as soon as the "swearing jar" has enough money in it. I figure it is $10 for the saw, and $90 for the aggravation I won't experience.