There have been server versions of garmins soft strap, I've had three and the most recent versions really good. I actually mount my wahoo HR monitor on it, as it's way better than the wahoo strap.
I use the Polar strap with my Garmin transmitter, and have done for the last couple of years. It's both comfier and far more reliable than the Garmin strap. You have to cut off the rubber surrounding the strap's poppers with a sharp knife in order to attach the Garmin transmitter.
