I've installed plenty of customer supplied thermostats, including the Nest, but when it came time to upgrade the thermostat in my home I was forced to do a little research. There are so many new thermostats on the market now...the research took awhile. I began with the Nest. It looked cool, seemed popular and I'd heard a lot of good things about it.
When researching the Nest, it seemed like most of the complaints I read came from people installing the Nest on a 4 wire cable. Based on what I've read, I would not trust a Nest on a 4 wire cable 
- too many people waking up to 88 degree houses. After doing my homework, I decided to try the Honeywell Wi-Fi smart thermostat because it seemed simple to use and the reviews I read were very positive. The Honeywell instructions clearly stated that a five wire thermostat cable is required, so I replaced my four wire cable and installed the new thermostat.
The initial setup was easy and connecting the Honeywell thermostat to my Wi-Fi was simple. I've been using the new thermostat for the last 3 months and I couldn't be happier. I routinely use my cell phone to check and control the temperature in my home and the app for android has been flawless so far. I can turn on the heat or air conditioning and toggle the temperature settings from anywhere I have cell phone service. The thermostat schedules are fully programmable and the security feature is great. 
Security can be set at different levels of permission with the highest level being a full screen lock, requiring a password to operate.
The Honeywell smart technology is a simple feature which "learns" about your furnace capabilities as opposed to the Nest which seems geared toward automatically learning your family schedule. The Nest just seemed a little too "smart" for me and our always changing family schedules. We will be doing a similar review blog post on a new Nest user - one of our electricians who has installed the Nest in his home was kind enough to chronicle the installation and use. He has been using it for about a week and he says so far so good.
If you have an opinion on a smart thermostat you are using, please comment - we'd like to hear your thoughts! Or give us a Call at 612.385.7864
Thanks ^_^