Long GPS endurance, trail tools, and optional inReach make the watch appealing for very long races. Solar is particularly compelling when runtime matters more than a colorful display.
Pros: battery life, mapping and navigation
Cons: value for money, LTE connectivity
Solar endurance, large-model runtime and consolidated multiday records suit ultrarunning well. Smaller AMOLED models and reduced GPS runtime can require charging or a specialist alternative.
Pros: mapping and navigation, battery life
Cons: value for money, software smoothness
Long GPS endurance, detailed maps, and geotagged notes are useful for ultra-distance running. Suitability depends on event duration and settings, and variable-effort ultra racing can expose wrist heart-rate errors.
Pros: battery life, GPS accuracy
Cons: value for money, menu navigation