I would have to respectfully disagree. My background is network engineering. I chose SmartThings initially specifically because it was using two well-established reliable standards, Z wave and zigbee. As long as you take the cloud out of the picture, there are many implementations with these protocols that are rocksolid.
At the low-end in home automation, indigo runs only Z wave devices and is extremely stable. At the very high-end in home automation, control 4 runs zigbee, and no one would pay their prices (typically 10% of the cost of the house plus an ongoing annual fee) for an unreliable system.
Zigbee is used for monitoring systems in hospitals, for most smart meters, for cable settop boxes, for the Phillips hue lighting system. These are all low maintenance, mostly set and forget systems.
Z wave works particularly well for light switches, and the Leviton line with their own simple controller is extremely reliable.
The standards are not the problem. If you buy very cheap offbrand devices you can run into issues, but that’s true of any electrical device.
Other than that, the reliability issues come from the cloud and trying to operate a multiprotocol platform with a $99 hub.
There are a number of alternatives to SmartThings. Most are much less versatile and flexible than SmartThings, and several work with only one protocol. But stability is not the issue for most of those competitors that are not cloud-based. Missing features are typically what bring people to SmartThings.
Every system has pluses and minuses, but the standards are not to blame for SmartThings’ stability issues.
Submitted with respect.