I love mine. It gives me a little more incentive to get up in the morning. The mini me screensaver reminds me if it's been too long since I've gotten out and just in general it helps me track my progress. So yeah I thought it was totaly worth the $30 or so I paid for it.
I haven't tried it but just an FYI, Pedometer battery is not replaceable so you'll eventually need to buy a new Sport Kit. And from what I hear it's available only for iPod Nano.