I have come to admire the Polar H10. When I bought it, it only came with Bluetooth support (no ANT+) and the Polar apps were crap. Since then, I have come round to it and now recommend it.
First off, a firmware update added support for ANT+. Second, it works well. I use it on Zwift because it maintains my heart rate and does not seem to drop out. It is also very comfortable to wear and the strap clicks into place rather than the hook system you get with the Garmin range. Changing the battery is also toolless. You just pull the battery cap off the unit (although you may need a screwdriver to get in there!) and stick the new one in. It uses CR025 rather than CR032.
It supports two simultaneous Bluetooth connections should you need that, and mine syncs with the spin bike at the gym, too.
There are downsides. Like all Bluetooth heart rate monitors, it is larger than ANT+ only ones. And it doesn't sync very well with Garmin watches while swimming. And the apps aren't great: confusingly, they have two, Polar Beat and Polar Flow, but you do not need to use them.
The Garmin HRM-Tri remains my heart rate monitor of choice when I am using ANT+, but for Zwift, spin or any other time I just need to grab a heart rate monitor, this is the one I go for.
We use a simple one, two or three star rating system. One star for stuff we do not like, two stars for gear that is okay and three stars for equipment we recommend. We awarded this product 3 stars. All reviews and ratings represent our opinion only.