When I first started to look I figured between Z-Wave and Zigbee there should be a number of good choices...... I guess not.
It sounds like either the 5 or 6 would suit my purposes, but having a more obtrusive "doorbell button" with battery needs doesn't thrill me.
Right now I'm looking at the AVANTEK (not so smart) door bell and button. My thought is to take the button apart and using a relay of some sort, have it energized by my current doorbell (simple button).