Navman M300, GPS as a pedometer?

I’ve been trying this Navman M300, the marine model in a  new line of small GPS “Sport Tools” designed to strap to your arm while you windsurf, skate, ski, run, or walk. It delivers speed, heading, distance covered, lap times, etc., but not position or “go to” guidance. And it will not interface to a PC for data collection or waypoint passing. Both interface and tightly defined purpose are KISS (keep it simple, stupid) ideas, largely I’m guessing to differentiate the Tools from the various Garmin Foretrex and Forerunner models that dominate this niche. There are only two buttons and about six choices for the text screen (which is small but readable in all daylight conditions). The firmware for some models seems to have especially valuable features—like the way the ski model leaves the lift segments out of your speed averages and distances—but personally this marine model doesn’t excite me (learning how Richard Stephens uses his Foretrex did, but that’s me). I’m also dubious that “reliably water resistant” is good enough for wind surfers; I know that when I used to do it I’d spend a good deal of the time thrashing about while submerged up to my chin! Then again I would like to know how blindingly fast I was going when I had it together. By the way, the 19 knots max speed above was on my bike, going down a steep hill. I need to exercise more.

Update, 9/2: My doubts abut the windsurfing model may be off base. I’ve now learned that they were used successfully for the Maui Speed Challenge (yes, Navman was a sponsor, but these are the top guys and wouldn’t tolerate a product that didn’t work well).