I have a collection of Heart Rate Monitors which includes the Polar H10 (and the H9, which is exactly as good except it only has 1 Bluetooth channel). The H10 is an electrical chest-strap HRM, with a longstanding reputation for accuracy. It seems to burn through batteries relatively quickly, even when the pod is removed from the strap between uses.
While the H10 is my gold-standard HRM, recently I find myself using a standalone armstrap optical monitor, the Polar OH-1 for daily use. It’s discontinued, but there is a newer model. The optical monitor is probably not accurate enough for looking at heart rate variability during a ride, but for average heart rate over any multi-second interval it is probably fine, and that’s good enough for me. It has an internal rechargeable battery.
When training indoors, several times recently I have had chest-strap monitors lose the signal because of excess sweat. It only occurs when I am really hammering, but it is a burden that I need to be watchful and keep an extra dry towel within reach. Not a problem I have heard others complain about, but optical armband monitor doesn’t have that issue.
Chest-straps need to be replaced periodically, their electronics don’t. I find that with Polar monitors it is worth buying the manufacturer’s replacement strap, because their snap-in connector is more than slightly different than competitors’. Plus, quality…. Recently the Polar H10 straps have been out of stock, the only way to get a Polar strap is to order a complete new monitor, although I haven’t checked again in the past week or so.