I own one of these, and I love it. I get the best looks when people see it drawn and seemingly already be open. Probably one of the best knives I own for the "Woah, that's cool" factor.
Beyond the coolness, it's a very effective knife with someone who knows how to use it. I've never formally trained with it, and I would love to get a trainer version of it, I have done my own draw drills and incorporation into my already formal training of Kajukenbo, Muai Thai, Tae Kwan Do, and Sanjuriu Jujitsu, and my informal in about ten other styles. It's easy to adapt to self defense wise if you understand human anatomy (especially from a martial arts stand point).
I've never really used it as a utility knife, mainly because I wanted to keep it as sharp as possible. I carried an Endura 4 Waved in my back right pocket for all my utility purposes.
It's one of my favorite knives I own due to it's speed, size, and ease of use. When I first handled it in the SFO, the lady working (I don't remember who off the top of my head) was advising me to try the trainer first for drawing because it takes practice. I drew it flawlessly mid sentence and when asked if I'd handled one before, I told her I hadn't and that I was able to do that because of the videos I'd seen on it. With that said, this is definitely a knife that I would strongly suggest playing with and handling before making up your mind on.
Greg