The neat thing about these is you can get nearly real time usage info on your hydro company's website.
The down side is tiered billing. You will now be paying more per kwh based on the time of the day.
I remember before these came out here the hydro company sent people a kit that you put on your analog meter and it was basically a sensor that looked at the wheel and sensed the black mark. Essentially it was a power meter so you can look at your real time usage. It was actually really cool. We had this wireless receiver and as soon as you turned on the oven or a light or anything the kwh would change.
Then a month later they installed the smart meters, making this new toy obsolete. Wonder how much money they spent on that.