I switched to COROS from Garmin after reading too many posts about battery life and GPS accuracy on long runs. Six months later, here's where I stand.
What Works Well
Battery life is genuinely exceptional. I can run 4–5 hours with GPS and heart rate on and still have charge left. On long training weeks this matters — I don't want to think about charging.
Heart rate accuracy is solid for steady-state efforts. During threshold sessions where pace and HR are fairly stable, the wrist sensor tracks well against chest strap comparisons.
The app and API export your data in a usable format. I built my own analytics dashboard on top of it — if COROS didn't let me get my data out, I wouldn't have kept it.
Where It Falls Short
HR accuracy during intensity spikes is noticeably behind a chest strap. For VO₂max intervals where HR is climbing fast, there's lag. Not a dealbreaker for Norwegian Method training (where most work is steady threshold), but worth knowing.
The native app is functional but basic. I don't use it for analysis — that's what this site is for.
Would I Buy It Again?
Yes. For the price, battery life, and data accessibility, it's the right tool for the training I do.