I tried the Suunto Race in a shop just weeks ago, and I’ve seen user reviews even more recent than that mentioning the lag, hence my concern and hesitation.
But I’ve just found this side-by-side comparison with a Suunto Race, and the Suunto Ocean looks as smooth as any smartwatch or fitness tracker out there: https://youtu.be/uiyPGzNpOt4?t=1796
Now I’m very interested.