I have the Nike Sportband II (the watch with a USB captor that plugs into the computer, with a sensor on the shoe). It has its limitation but it's fine.

I think it's great. I live in a very hilly area and since calibrating it (on a hilly run) it's been about 3-5% off most of the time, never more than that.

I like that it gives me instant information about my pace. I know it's not totally accurate (it's under-calibrated, which makes me feel better knowing I'm actually running faster) but it's enough for me.

It has even changed my running habits. I used to be mindful of where I ran because I would have to map my run afterwards. Now I just run and the gizmo takes care of figuring out the distance.

What I dislike is that I cannot save the data on my computer. It all goes into the NikePlus web site.

For now, overall: Love it!