"Sadly, I am in love with my thermostat."5.0 starson by GuMeng
Pros: So easy to install and use. Gorgeous interface. I often stop to look at it just because it is there. Its like art on my wall. And it does a smashing job at heating and cooling. Oh, and yes, I have seen a savings in my energy bill already.
Cons: Price. I needed two for my house, so that's a whopping $500. If you can afford it, it is great. But it is a lot of money.
Summary: If you can afford it or you can look at the long term savings, then get it. It is sadly one of my most favorite gadgets in a gadget filled house. The iPhone/iPad App works great, too. The most fun you will ever have with a thermostat. If that doesn't sell you on it, well, yeah...