I purchased the Emfit QS in January 2018 and have spent the last year sleeping with it. First, it is non-evasive. You don't have to put anything on your body, turn anything on or start/stop anything before and after sleeping. You simply lay in bed, it senses your presence, begins recording and uploads your data during the night to the Emfit servers. When you exit bed in the morning it recognizes it and begins to put together a picture of your night of sleep. By the time I have my coffee made, I can jump on my phone or look at my computer and get all the data. And there is a ton of data it provides: sleep time/score, breakdown of light/deep/REM cycles, HRV w/ nervous system balance, avg and resting heart rate, respiratory rate, movement/restlessness and finally a proprietary recovery score (that probably still needs some work).The next question people ask is: are the metrics accurate? I also wear an Oura Ring 24/7. It, like the Emfit QS, tracks all the metrics mentioned above. When comparing the results of the two devices, while not matching exactly, show a very clear correlation. They are identical in the sense that when one shows a lower HRV or high HR, the other device has recorded the same trend. Then you have to look at the results provided by the QS and compare it to what you think should be happening, I've found they gel. For example, I was in a bad bike vs car accident in April 2018 that knocked me out of triathlon training for about 5 months while I recovered. During that period the Emfit recorded much high HRV values while recording high resting heart rate values as I lost fitness and aerobic conditioning. Weeks after returning to training, HRV numbers began to drop while my resting HR lowered as well.I have tried several different sleep trackers and HRV/HR measuring tools. This and my Oura Ring are 1 and 1a on the list of effective devices. If you are looking for a hands-off biohacking/recovery measuring/sleep tracking tool I would highly recommend this.Let me cover some of the negatives. I had, and others have reported, some connection issues with their home WiFi. I did find it quirky when I first set it up and had difficulty getting it to connect. Once connected though, I have had no drops and there has not been a single night that data was not recorded. Next, there is no option to place it in airplane mode. There is no internal memory to record during the night and then upload the data later. The device it constantly reaching out to your WiFi every six seconds and uploading data while you sleep. For some concerned about having a WiFi signal that close to you every night, this may not be the device for you. Having said that, the Emfit QS does come with a long power cord and a transmitting device that you can place up to six feet from your bed. Nevertheless, a semi-easy update to this device would be a 2.0 model with internal memory that can turns itself off, record your data all night and then turn on and upload the recorded data once you out of bed. Lastly, if you spend a lot of time in your bed, say watching TV or reading before you sleep, the device night confuse it with you attempting to fall asleep unsuccessfully. I read for at least 30 minutes before I turn the lights off. I found that if I just get out of bed to check if the doors are locked after reading, the device recognizes my sleep patterns enough that it does not record the extra time.A couple of other side notes. I have a Tuff N Needle memory foam mattress. It provides no difficulty in getting any bio-metric signals through it. It also does not pick up my wife's signals when she sleeps, even if we are up against each other.Overall it has proved to be a solid device that provides good, valid sleep and recovery data.