Polar H10

Polar H10 or the new HRM dual with machine washable straps

Also compared the heart rate measurements between the watch and the H10 from Polar, and they are almost perfectly identical.

many people tell me to go with the h10

Chest HR is going to be way more accurate than the majority of watches. I would recommend Polar H10

I use a Polar H10 (chest strap) for running, weight lifting, and hiking. The heart rate monitor works great and for me it is more accurate than the apple sensor.

The Polar H10 is one of the better ones and I've had great use out of it running and cycling

my own H10 has never given me a single problem

If you want to get accurate exercise HR readings, you need to get a chest strap like a Polar H9 or H10.

I use HRM dual and polar H10. Very similar, both are good (reliable readings) neither infallible (connection issues sometimes in wet and cold weather). ... The H10 can save a workout solo but you need to start that from the polar smartphone app separately so not as practical in a pinch as you would think. Probably nice if you want accurate readings for a swim.