Surely if you let a pacer catch up with you, your chip time is going to be slower than theirs?
I appreciate that if your goal is to simply get round, this wont be an issue. However, if you start in the 4:30's pen and let the pacer for 5:00 catch you, your time will be slower based on the fact you crossed the start line earlier.
I've been very happy with my Nike+ watch and footpod. It's to within a couple of metres of the My.Asics GPS app. Only issue I have is with using the footpod on its own. Tried it on a treadmill a couple of weeks back. Nike said I had run 5 miles, when I only did 3 and as a result completely smashed my PB for 1k, 1 mile and 5k.
Had to delete the run, although I did quite enjoy having a 4:31 mile on my watch for a short time