Nest so far.
- Our electric bill last month was negative three dollars. I think it is unrelated, but funny to note. Still, there is a little green leaf that shows up on the screen when you have your temperature set to use less energy than previously. It is sort of motivational!
- Every time I walk by the Nest it lights up and shows what the temperature is and what the heat or a/c is set to. This is fine and interesting but I always expect there to be a clock on it for some reason.
- We can control it with our phones. Sometimes we leave the air conditioning off, check the home temperature while we are out, and then turn it on when we are on our way home. This works great to cool down the house efficiently.
- It shows humidity levels. I didn't expect that but it is handy.
- It keeps track of how often the air conditioning is used so we can track exactly how much we have used it and what temperature it is outside so we know how much more or less we use it according to outdoor temperatures.
- It doesn't work with newer variable speed motor air conditioning units. Ours is an older model so it still works great, but if we upgrade we won't be able to use the Nest anymore.
I hope this helps! I will update it again after a couple months of Summer usage and after we get a more realistic electric bill. Let me know if you have any other questions about how to use it or what it can do.