After putting a bunch of GPS watches through some robust trail testing and long term experience with them we can do a ‘best fit’ for various runners. The runners described are –
Adventure and ultra-plus: battery endurance, accuracy in difficult conditions, reliability, navigation and back-country functionality.
Fast and furious trail racer: trail accuracy, reliability, and racing functions.
Budget trail runner: trail accuracy, +12hr battery endurance, and anything else we can get
Smartypants trail runner: trail capable, +12hr battery endurance, smartphone features
Roadie with a bit of trail on the side: like the fast and furious, but with less trail features.
The watches in the 2015 test pool were: Garmin’s FR310XT, FR910XT, fēnix 2, and fēnix 3, Polar’s V800, Suunto’s Ambit2, and Ambit3 Peak.
Note: not all these unit’s have full write ups yet but they’ve all done the time. Write ups are on their way.
Adventure and ultra-plus
First pick: Suunto Ambit3 Peak, unrivaled in the category. More accurate with more endurance than anything else tested, combined with absolute reliability and best navigation functionality.
Runner up: Suunto Ambit2, like the newer Ambit3 Peak but with less endurance and a few less features.
Fast and furious trail racer
First pick: Garmin FR910XT, not quite the match of the Ambits in terms of accuracy (is prone to extended track shadowing), but has a more race friendly design and feature set (screen legibility, vibrate alerts, button placement/feel, virtual pacer).
Runner up: Suunto Ambit3 Peak, while a more capable unit in most areas, it just loses out on the specific demands of blurred vision racing.
Budget trail runner (if you can find them)
First pick: Garmin FR910XT, pretty obvious really. Is more accurate with more proven endurance than the fēnix’s. Can’t be used day to day, and is prone to a bit of off-track meandering from time to time.
Runner up: Garmin FR310XT, pretty much like the 910XT without the altimeter. Also is orange and a bit bulkier.
Note: If there were a market for 2nd hand Ambit2’s they’d be worth a look too.
Smartypants trail runner
First pick: Garmin fēnix 3, more features than you can count on both fivefingers. Great looking, user design is excellent, and pretty impressive smartphone integration for a trail beast. Is held back by poor real world battery endurance and middling accuracy in tree cover.
Second pick: Polar V800, solid smartphone notifications, nice screen and easy to use design. Doesn’t quite cut is a full featured trail watch though, pretty accurate outside tree cover but stated distance a bit variable in the trees.
Road with a bit of trail on the side
Too hard to pick.
Suunto’s Ambit3 Peak is super accurate, has some great road running metrics, screen a bit average and lacks vibrate alerts, advanced workouts/interval training dependent on mobile app which still a bit iffy on Android.
The Polar V800 is fantastic on the road and urban trail, save the bulky pods, some proprietary issues, and general lack of trail features. Also often slow to acquire GPS.
And the Garmin FR910XT is still a class act on the trail and road, though can’t be used as a day to day watch and acquisition time is a bit painful in comparison with modern caching GPS.