Add to this the gymnastics involved in building in the power management features to get to a ten-hour-per-charge duty cycle.

ENGADGET: DirectVoxx muso voice control accessory is more expensive than the iPod

These WD customers demand AV-grade drives, which are specifically engineered for recording and playback of programs on a 24-by-7 duty cycle.

ENGADGET: Western Digital refreshes My Book DVR Expander HD

Most are alkaline batteries, discarded after a single duty cycle.

CNN: The dirty dozen: 12 products you should avoid

Power and duty cycle: This is one of the critical flaws in the Surface Pro, and in my view, will be a real negative to anyone that wants to use this as a substitute laptop when traveling.

FORBES: Why You Want The Microsoft Surface Pro (And Why You Don't)