Power meters and where they go

Some of you may have read the recent Slowtwitch article about the redesigned Pioneer Electronics power meter crank.  Cranksets are the most popular spot for power meter placement.  With a crank-based meter, you're not locked into using one rear wheel all the time, as you are with hub-based meters.

Here's a list of crank-based power meters:

Pioneer:  Dura-Ace and Ultegra 11-speed crank options.
Quarq:  These are the cranks we see most often.  Two main options, the Elsa and the Riken.  Owned by SRAM, and compatible with Shimano 10-speed drivetrains.
Rotor:  Left and right leg power measurement; just 3 crank length options.
SRM:  Lots of options, based around Shimano, SRAM, Campy, and other brands of cranks.
Stages Power:  Measures from the non-driveside crankarm only.  One of the cheapest options.
Verve Cycling:  InfoCrank, 50/34 tooth chainrings, (taking preorders).

Pedal-based meters are a recent addition to the market.  The Garmin Vector and  Polar/Look Keo Power pedals work with most cranks.  Of course, they do require you to use said pedals, so you have to use the matching cleats, too.

Hub-based meters, available from PowerTap, can be less expensive, depending on which hub you choose and which rim you build it into.

And finally, there's the under-cleat Zone power meter from Brim Brothers (available for pre-order).  It sits between your shoe sole and your cleat; I suppose that means you should be able to use any shoe, any pedal, crank and wheel.  Hopefully we'll hear more about it in August, when units are supposed to ship to folks who pre-order.