The answer to this question is similar to Which Beacons are the Most Compatible (with iOS and Android)? All beacons transmit to Bluetooth standards and use similar, certified, components which means there are no problems with compatibility or ‘best’ beacon for compatibility with an HR system.
Instead, we find the challenges usually lie in setup and getting the HR system to recognise the beacon UUID. Most systems use iBeacon advertising that uses a UUID, major and minor to uniquely identify the beacon. The UUID looks something like 3ce2ef69-4414-469d-9d55-3ec7fcc38520. Some HR systems use upper case for the hexadecimal digits that are letters, some use lower case. Some omit the dashes (-) and some use colons instead. Read your HR user guide to determine the exact format otherwise the beacon won’t be recognised.