I‘ve been using ZoneSense since release, I will add another data point:
Training: it‘s super useful in staying aerobic without worrying about whether my HR zones are set correctly, and it adapts to my form on the day. So 80% of my training runs use a ZS Zone 1 target, with an alarm on my watch if I stray into Z2 for too long. I do not use it for any speed work in training.
Racing short: without a clear ZS target zone (e.g. „you can hold ZS 2.8 for 45 mins“), I don’t see much use to ZS for half-marathon and shorter races. Or any race event under 90 mins. So I stick to pace (track and road races) or power (trail) targets.
Racing long: this is more interesting. For example in a marathon or trail race > 120 mins (not a hard threshold, this is subjective), I know I cannot spend any significant amount of time ine the red zone or I‘ll blow up later on. ZS becomes super useful again, especially paired with a pace or power target. I would follow my target pace/power but use ZS red zone as an alarm telling me to slow down and manage my effort better.
Since ZS was added as a target, I no longer use the Suuntoplus app.
