If you can wait til next year, there's a new "relatively" inexpensive power meter (read; about the same as a powertap) which fits into speedplay pedals and will be Ant+ compatible.
It's more than that though. There could be all sorts of issues with the new product.
Since PT has been out for ages its flaws are known and things like Training Peaks (best sw for use with power meter) works with it. You are also limited with pedal choice, etc. Basically, I wouldn't be rushing into one of those pedal-based systems until quite a way into their life.. once most of the flaws are ironed out, they work with Trainint Peaks and they work with SPD-SL. I love the idea though.
It's more than that though. There could be all sorts of issues with the new product.
Since PT has been out for ages its flaws are known and things like Training Peaks (best sw for use with power meter) works with it. You are also limited with pedal choice, etc. Basically, I wouldn't be rushing into one of those pedal-based systems until quite a way into their life.. once most of the flaws are ironed out, they work with Trainint Peaks and they work with SPD-SL. I love the idea though.