Brett - not wishing to burst balloons, but youll find these not-that-accurate for some loads. For the behmor - it is probably pretty close since it is probably a simple resistive load.
Youll find it probably over-reads power usage for things like your computer or TV - anything with a switching power supply.
There are rather more expensive devices that measure the true power consumed. The "Power Mate" device from CCI does this (Im biased - a colleague wrote the software for this - the ADC has something like 18bits of resolution - it can measure the power chewed by a neon lamp!).