So far, so good. The videos offered on the Nest website made installation seem pretty easy, but mine wouldn't work right - no cold air from the AC. I went back through the instructions a number of times, looked online at user install videos - couldn't find anything that was helpful. Finally called Nest support. They answered straight away, and asked me a few questions, then asked me to upload the photo I'd taken of my wiring with the previous thermostat. I tried, but couldn't seem to get the image uploaded. While we were struggling with that, the technician asked me 'is your unit a heat pump?' When I replied 'yes', he said he thought he knew what the issue was. He had me attach a wire that wasn't covered in the install manuals, and it worked. I looked back through the instructions, and didn't find any documentation on how to connect the wires if you've got a heat pump. I'm sure that there's a LOT of homes out there with this type of AC unit, so perhaps there could be some clear documentation for that type of install put out there where it's more easily accessible.
For simple installations, the provided documentation is pretty easy, and you can install this unit yourself with a minimum of trouble. However, if you've a more complex setup - zoned ACs, for example, or a heat pump, it's a bit more complicated. Even with a simple install, there's a LOT of advanced settings that aren't clearly explained. Like primary and secondary heat settings. Heat pumps have both, but I couldn't tell you which is which, or if my Nest is wired to properly take advantage of that feature. Or a setting that asks me how long I want to 'preheat', with the default set to 5 hours. I've got no idea what that means, and haven't been able to find any Nest documentation that talks about that setting. I've a lot of questions to figure out if I'm using the best settings for a heat pump in North Florida, and so far not finding any helpful documentation.
That being said - it's working fine, and is saving me energy. By installing the app and tying it to my phone, the thing knows when I'm home and away, and goes into Eco mode when I'm away, which pretty much keeps it from running. Now that a few weeks have gone by, it has figured out my schedule, and starts to cool the house minutes before I get home. I looked at the schedule it created from my comings and goings, and I can see that it knows when I'm home, when I'm away, and knows when it's the weekend and that I'm home - the schedule it created on its own is a pretty clear indication the Nest knows when I'm around and when I'm not. It connected quickly and smoothly to my amazon echo device, but haven't used that feature a lot yet.
I feel like I've gotten my money's worth from this device, and feel confident that I'll find the answers to my questions about the heat pump setup. It may already be set up correctly, but I want to know that I'm getting peak performance out of my AC, and I can't be certain I am at this point. I'll update this comment once I find that information.