3 is great, if you are really serious about running metrics get a Garmin, but I bought a 3 to try out last December and never looked back, so easy with airpods running with music. Counts laps in the pool, open water swim tracking is excellent. HR is fine for all day tracking, for sports tracking it’s a bit hit and miss depending on what you’re doing and conditions but if you are serious about this then just get a chest strap.