Z-Wave. I could never get it working quite right despite purchasing highly recommended Aeotec stuff.
The MultiSensor 7s and door sensors would always report a battery level of 100%, fall off the network, and do other crazy stuff. I spent a year with a Z-Stick 7 before finally bailing a buying a fifth generation stick.
Firmware updates would take weeks because they just wouldnβt install. Constantly factory resetting them never fixed anything either.
I really hate to say it, but Zigbee ended up working much better despite living in a 2.4GHz interference hell hole.