Mapawatt has personally tested this product and recommends it for all users!

The eGauge energy monitor is a very robust home energy monitor.  We had experience communication issues with our TED 5000 (it also uses powerline communications to get data from your breaker panel to your computer) and we did not have these issues with the eGauge.  However, the eGauge is more than double the cost of the TED 5000, so review each product if you think directly monitoring your breaker panel is the best option. 

Our favorite feature of the eGauge is the web interface, where all your data is hosted for free. An example can be seen below:

Aside from the web interface, the other great feature of the eGauge is you can monitor several circuits in your electrical panel, and also monitor any clean energy (represented as the green line above).  When we tested this unit, we monitored the main power lines, the AC unit, and the refrigerator.  The only thing to be aware of when configuring your egauge system is to ensure you select the right amperage of the current transformer you are using, as there are several options.

The eGauge is robust enough for commercial applications as well.  If you have an office with a solar array, you can show production on the company's website or intranet.  You could also demonstrate to employees how much energy is being used/wasted at different times of the day.

Advantages: Robust powerline communications, free web interface, multiple monitoring options, suitable for commercial applications

Disadvantages: More expensive than entry level home energy monitors