This is my personal review on the Ecobee3 Lite smart thermostat. I've had this thermostat for just about a month now and have been trying to learn most of its features since then. The first thing you must know is that this device requires a C-wire for power since it does not have a backup battery. This may be a challenge or a problem for a person who has little-to-none knowledge of how HVAC systems work as it will require the user to run an included adapter (Power Extender Kit) from your HVAC system which will eventually provide power to the Ecobee3 Lite thermostat. The instructions are very straight forward but again, if you do not feel comfortable opening your HVAC system and connecting the wires to the PEK, I would recommend to hire a licensed technician to do the work or buy a different smart thermostat that does not require a C-wire. Otherwise, the installation takes roughly half an hour (which is what it took me to complete with no prior experience of replacing/installing a thermostat).Out of the box, you get the thermostat, wire labels, a white backplate (in case you need to cover any holes from your previous thermostat), the Power Extender Kit (PEK, in case your thermostat does not have a C-wire), a backplate (to connect the wires), a couple of screws & wall anchors, and the installation manual. You will need a precision screw driver to remove wires from the old thermostat, a 3/16" drill bit, a phillips screw driver and a drill to facilitate the installation. If you do not have a cordless/corded drill, you can still get around with the installation but will take some additional time & effort. Remember to always follow safety procedures before working with electricity around your house to avoid serious injuries.Now onto the features I've tried so far. The Ecobee3 Lite supports a wide variety of third-party integrations such as Alexa, Apple Home Kit, Google Assistant to name a few. This gives a wide range of users to be able to control their smart thermostat with their voice, smart phone or automation. When you are initializing setting up the device, you are greeted with an Ecobee welcome message. You then have to give it a name, configure your Wireless network for communication, and most importantly, register your device. The device has three different comfort settings; Home, Away, and Sleep. These settings can be modified to your needs which can then be added to your weekly schedule with a specific time to run them. If there is one annoying thing I do not like so far is the fact that you cannot remove all comfort settings for a specific day from your weekly schedule. It must have at least one comfort setting to run unless you turn off the HVAC system from the thermostat. The thermostat by default comes with the "Smart Recovery" feature enabled, which Ecobee support said this feature allows your thermostat to understand your AC/heating pattern in how long it takes for your home to get to the desired temperature from your schedule. The thermostat takes into account the performance of the HVAC equipment relative to the effects of the inside temperature & predicts how long it will take to bring your home to a given temperature. This basically means that if you have your schedule set to "Away" mode from 8AM - 5PM (to be within a certain temperature range before it turns on your AC/heater), and then starting at 5PM you have it set to "Home" (again to be at a certain temperature range), it can still turn on your AC/heater during the "Away" mode in order to get to the desired temperature by the time you get home at 5PM, for instance. I do not like this "Smart Recovery" feature as the purpose of the "Away" schedule I set up is so that the A/C is never on while I'm not home. If you are like me, you can turn off this feature directly from the thermostat by going to Main Menu > Settings > Preferences > Heating/Cooling Smart Recovery. I also like the fact that their software is very similar across all platforms (mobile apps, website & thermostat screen), this makes it a lot easier to navigate around without having to learn it all over again when using a different device. You can also restrict access control to the thermostat by setting up a code in order to access the system. This is great if you have kids in the house or if using in a shared environment such as an office where only certain individuals may have access to change its settings without having to install a lock box on.The Ecobee3 Lite supports the proprietary room sensors, which can be added to different rooms and balance the temperature around your house. This is probably more suitable for two-story homes or bigger homes where temperature ranges drastically at certain times of the day. If you have a newer home with an open-floor plan, these sensors may not be very useful. Below is a summary of the Pros and Cons I have found out so far:Pros:- Compatible with Alexa and Apple's Home Kit & Google Assistant.- Uses geofencing to detect when you enter/e...