I agree that they're not all that easy to switch between bikes. They're slightly more involved to install than a pedal; you've got to use a torque wrench to get the torque right, and you've got to calibrate.

I would not recommend to anyone buying Vectors for the purpose of being able to swap them between bikes. Its quicker and easier to swap a Quarq or a SRM than it is to swap Vectors. I used to swap my Quarq from road bike to TT bike. It's a 3 minute job, and can be done easily between stages in a stage race when road stage and the tt stage are close together.

As for bashing the pods doing cyclocross or Mountain biking, your experience definitely would indicate that Vector may not be a great choice for those uses, and that certainly makes sense.

I do think there's a pretty good case that they're the best option right now for a tandem, albeit a pricey one.