High on my Christmas list (yeah sure, I haven’t been that good this year) how I’d love a set of PowerTap P1 powermeter pedals. I love my G3 hub, but it does mean you’re limited to using it only in the one wheel. PowerTap P1’s give you the option of putting your powermeter on any bike simply by switching pedals. It is a very expensive way to basically tell yourself to pedal harder though!
There’s no need to a torque wrench when installing to ensure accuracy either unlike the Garmin Vector pedals, making the P1 pedals the most portable and transferable powermeter currently on the market.
The biggest downside I can see with these (and all pedal based powermeters) is that pedals are easily damaged in a crash, drop your bike, scrape them on curbs, etc. Here’s a little video from the GCN boys showing how they’re made and tested: