I bought the Biostrap 3 months ago to monitor recovery after an infection caused heart and lung issues. I use it nightly and the data stops me over exerting myself. The trend data gives me insight into the whole recovery process. I also bought EliteHRV but only used it for a month - the Biostrap gives me more comprehensive results. I design and program products for a living. I'm impressed by the Biostrap. The user interface is brilliantly designed, simple to navigate yet using techniques to creatively display a wealth of information. Well done! While some complain of long sync times, my Biostrap and phone are set to sync every 10min, so at night I see results instantly in the morning. I've only seen long sync times (4min) when the phone and strap are out of range for 12 hours. If you're using it for training recovery, the sleep data is very comprehensive - highly recommended. For physical training I'd use another device with a visual display and different sensor. For those interested in researching, check out the page: "Red vs. Green: Does the Light Sensor in Your Wearable Matter?".