Wouldn't be without it!
We have one in our Wisconsin lake home as part of our security system. We can phone from home, punch in a code, and the furnace automatically turns up to our preset temp. (We keep it at 55 degrees when we are not there).
On the other hand, if the temp goes below 45 we get a call from the dispatch. And yes, it paid for itself one February night at 2 AM when we got the dreaded call and made the 2 hour drive to find the igniter on our 3 year old furnace had failed.
It was about 30 below zero, and the pipes would have frozen by morning.
If the power goes out during a storm we get a call when it fails and when it is restored. This summer it was out for several days so we knew we had to get someone over there to get the steaks out of our freezer.
Our system is Ultraguard, and it was purchased and installed through our power co-op.
Did I mention it calls the sheriff if someone breaks in?