Been bouncing between a Vertical (current), a Race (briefly), and a Fenix/Epix. Short version from actual use on 30-50k trail days:
Navigation: Suunto’s maps are clearer at a glance and offline downloads are dead simple. But there’s no on-watch rerouting; miss a turn and you’re manually finding your way back. Garmin’s maps are routable, does turn-by-turn from the map, reroutes, and ClimbPro is still best-in-class for upcoming climbs. If you rely on on-the-fly course changes, Garmin wins.
Elevation: Suunto’s FusedAlti is boringly reliable once it settles (I hand-calibrate at the trailhead sign if it’s off). Garmin is fine but I see more drift on stormy/windy days. Whichever you choose, rinse the baro port and avoid jacket cuffs sealing it-most “bad elevation” is blocked ports.
GPS lock: Both are fast with dual-band. My Vertical usually locks in 5-10s open sky, 15-30s in conifers; Epix/Fenix with SatIQ is a hair faster and less finicky when you start under trees. Tip: wait for full lock and HR before pressing Start; it matters in canyons.
Battery: Real-world numbers with dual-band + maps: Vertical 2-3%/hr, Epix Gen 2 4-5%/hr, Fenix 7 Pro 3-4%/hr. Race (AMOLED) is closer to Epix. For 50k you’re fine on any, but the Vertical is the “don’t think about it” option.
Training insights: Garmin if you want the whole Firstbeat circus (Training Readiness, HRV trends, Stamina, suggested workouts). Suunto’s metrics are lighter and less prescriptive; great if you don’t want the watch coaching you, not great if you do.
Strava/app: Sync is instant on both. Suunto app is cleaner and has the best mobile route planner/heatmaps right now. Garmin Connect is data-dense and better if you live in metrics. Coros sync is also instant, but maps/nav and workout guidance still feel a step behind.
If your priority is dead-simple offline maps, excellent battery, and solid elevation for trail days, go Suunto Vertical. If you want dynamic rerouting, ClimbPro, and deeper training guidance, stick with Garmin. Race only if you want AMOLED and can live with shorter dual-band runtime.