Commercial, Medical Device, or Open Source
Often one of the most important features of a device is its license because this often determines many other properties of the device.
Commercial
The most commonly known and popular type. Sold for profit, to the average consumer and with absolutely on guarantees. Usually easy to set up and understand. Unfortunately exporting is not guaranteed and therefore comparing and predicting with data from other sources is hard, though workarounds can be found on github. No guarantees also means that the information the device pretends to measure could be completely made up. For an example buy an off-brand smart watch from any big online site. More commonly, the devices that really measure something often do not warn the user if the signal the device is getting is really bad. Perhaps some guarantees can be made through word of mouth and scientific studies.
Medical Devices
Like commercial but with an FDA guarantee[1] of sensor quality and therefore more expensive. No guarantee of data export and no workarounds. Usually devices for doctors to use will export the data to an app and a service for patients will not.