Introduction
I have been using Elegato Eve Motion for about 3 months now. I have to say, for the most part, it has been very reliable. I located it in my garage because it tends to stay a bit dark and with the use of it and some Philips hue bulbs, I can have the lights come on without fumbling around on the wall looking for a light switch.
Applied Use
We moved into our new home in November and unfortunately we had to get a counter depth refrigerator to fit our existing kitchen layout. We did not know how difficult it would be getting accustom to such little space in our refrigerator. In retaliation of our cold storage constraints, we decided to to put another refrigerator in the garage to provide a new home to beverages (beer) as these seemed to take up the most unnecessary space in our kitchen refrigerator. The problem, was anytime I wanted a drink I had to go into a dark garage. Elgato Eve Motion to the rescue! I got one of these from the local Apple Store and placed it just inside and facing the door. Once set up and running, I paired it with two Philips Hue White bulbs that light up the garage from above.
Set-Up
Set-Up is a real breeze with the Elgato Eve Motion. Once you open the package you will see the included AA Batteries. Just open the housing and slide the batteries in to activate it and find a place to place the sensor. You will want to make sure that you target an area 
you want to trip the sensor that is less than 8 meters away according to the company. To be safe and for best results though, I would try to stay within about 5 meters (15 feet) away.
Now that you have the batteries installed and the sensor set in position. Go to the app store and download the Elgato Eve application. You will need to register an account with Elgato Eve to get started.
Now that your account is set up proceed to the settings tab at the bottom left of the application. Tap add accessory to my home and wait for the accessory to be located. Tap the accessory to continue and follow the on screen instructions to finish set up.
Downside
Time Lag
Due to the product being connected via Bluetooth low energy sometimes it will take a few seconds for the motion sensor to respond. I have not had it completely fail on my yet, however, I have been inside the garage and nearly back inside before the lights actually come on. That being said I put the time lag to an average of about 3 seconds.
Only a Motion Sensor
Unlike many of the other products that Elgato Eve has in their line up, Eve Motion is only that. No other sensors are built in. Some of the biggest competitors for HomeKit motion sensors, at a bare minimum offer an ambient light sensor. This would come in handy to exclude activation of lights if the room is already bright enough to see, which would save money and energy. Philips Hue Motion ($39.99) has this feature and Fibaro Motion Sensor ($69.99) for HomeKit has Ambient Light, Temperature, and Tamper Sensors included in it’s much smaller housing.
Benefit
Wireless
The previous mention lag is also the reason for one of the biggest positives about the product. Due to the product being connected through Bluetooth low energy the product is completely wireless.
Long Battery Life
It also boasts quite a long battery life. As I said previously I have had the product running for about three months now and the battery indicates that it’s battery light has almost not been touched.
Customizable reaction
From within the application you can change how the product responds to motion. You do this by changing sensitivity to Low, Medium, or High. Elgato takes it one step further though and this is one of the most important things to note. You can customize the 
duration that motion is reported. This is extremely important for the way HomeKit works within iOS 10. Without the ability to adjust this lights would come on and go off rapidly as the device indicates no motion recorded. This allows you to have some delay before creating enough motion again to trigger the sensor and can be set to increments between 5 seconds and 15 hours.
Application
The Elegant Eve applications is hands down the most robust automation application I have used thus far. Customization of how your sensors and accessories react and are triggered is vast. That being said, it is not the most user friendly. For a really tech savvy person, the excitement of control would be fantastic. If you have trouble finding your calculator on your iPhone, it might take you a while to get the product to react the way you would like to. That being said I have been able to use Elgato Eve’s application to control third party accessories that would not have been able to function the way that I want through their own application.
The Future is Bright
I believe that sensors are the future of Smart-Home adoption. I wrote an article Misguided Home Automation Thoughts (HomeKit) explaining the role they will have in home automation and what we can expect in the future. That being said the latency issues created by bluetooth low energy in Apple’s HomeKit are said to be improved to a second or less in the upcoming iOS 11 upgrade. This should really help out Elgato’s entire line up of sensors in the near future.
Conclusion
The Elgato Eve Motion is a great product that has a very important role in the Apple HomeKit eco system. At a price of $49.99 it leaves a bit to be desired in terms of hardware options. However, If you are looking for a reliable and customizable product, with efficient battery life, then this may be the product for you. I would love to have 15 of these in my home to control lights and accessories in many zones. At a price of $49.99 it seems to be a bit prohibitive financially. Furthermore evaluating our current product climate that appears to be releasing many products regularly, I put this product in the the category of buy a few for special use circumstances and hold off on fully implementing these across your entire home. Once iOS 11 is fully released though with improvements that I think will greatly benefit this product line my mind may change. I will update as I learn more.
