I wonder how sensitive the buttons are on it? If you wore it hanging around your neck, it seems you could easily hit it with your needles when swapping them from hand to hand, and then accidently hit the buttons on the NKK counter.
Also, like Egeria said, if counts couldn't be saved, this wouldn't be very economical for the knitter who has several projects going at once.
I guess it depends on what kind of knitter you are, and how clumsy you are.
I personally wouldn't buy it, because I tend to write out my patterns stitch by stitch and row by row, and tic off the stitches I'm done with, so a counter isn't necessary for me.
BTW, I'm not OCD, just dyslexic and I lose count easily! lol.