I have a Garmin HRM that has been running fine for a year - I only use it for 3 or 4 rides during the week, so maybe not as much use as some of the others here, but it has been excellent. I've changed the battery a couple of times already. Bought a generic strap from Amazon as a backup, but I haven't even needed it yet.
FWIW, I just purchased the Viiiiva HRM so I could use my Garmin Ant+ sensors with Zwift on an iPhone. I didn't need a new HRM, but I figured I could use the Viiiiva as a bridge and then coax my wife into using the Garmin when she goes riding with me. Anyhow, the chest straps are interchangeable! I like the Garmin strap better, and it's already sized for me, so I just switched out the head units. Works great.