Michael Kisowwrote a review of Suunto Ambit2 S GPS Heart Rate Monitor on August 2, 2015
Familiarity: I've used it several times
I thought the "S" was better, like the iPhone6"S". In this case S means less battery life and also no constant elevation mode. There is no barometer. For measuring distances of hikes, it's great, but really sad that I can't see my elevation until I hook it up to the computer.