I've just switched from the Nike Sportband to the Forerunner 50 (with footpod and heartrate monitor). The Sportband is not very well built (display started whimping out after a couple of weeks), so I switched based on price mainly. Altogether cost about £70 for the full kit.
So far, seems stable over a known distance and the speed, pace calculations seem to be more precise according to my regular run. The Nike+ one being far more erratic.
The Forerunner 50 also records your cadence and speed, and the Garmin Connect web site is sorta like the Nike+ one, not as fancy, but pretty good.
Big plus, the Garmin actually has a light!
