I’ve found ST to be in the 90+% reliability area. Probably north of 95% actually. That’s still low enough that I’d never rely on it for something like managing a webserver that needs to be up 100% or for living saving equipment. But for the most part I’ve been pretty happy with it.
Only relatively recently have I started using it for high levels of security. I wouldn’t say it’s on par with monitor services… not by a long shot. But on the other hand, I wasn’t ever planning on getting any sort of monitor service so really it’s just kinda a bonus on top of my home automation.
RE: Presence sensors: Once I put a SmartSense motion sensor… plugged in… in my garage, my sensors have been rock solid. In the many months since I did this the only time I suffered from the wandering sensor issue I track down to be an problem with the sensor. Someone had bumped it enough that the power cord came out and it was just running on battery.
Generally I’ve been happy with ST. I certainly understand if others aren’t. I may just be lucky as well that I haven’t noticed the delays or downtimes as much (though I did notice issues last night for a while). But I also feel that anything you introduce complexity into a system, you have to expect additional problems. You know what will never fail? Putting the dumb switch back in the wall and manually flipping on and off your light.
I know that sounds a bit condescending but it isn’t meant too. I’m just trying to say that with a more advanced system we have to expect some level of problems. with it. Of course everyone has to decide what the acceptable level of problems they will tolerate before they throw the complex system out. For me, the current performance level is sufficient to keep me from looking to throw it away. Not that I don’t want better performance, but I’m not at the point that I’m ready to scrap anything.
This might be partly mitigated by the fact that there are perhaps only three things that “automated only” in my house. That is to say, nearly everything still have a manual override ability: Light switches or button on outlets can always be used to turn on/off things. I will have my normal garage door openers as backup for the automated system. With a non-geek wife I’m been sorta locked into make sure that she could still use the house in the event of a total ST failure. Nothing would destroy her acceptance of ST faster than her not being able to do something that she needs/wants to do because ST happens to be in a rare “unresponsive” mood.
Final note to a terrible long post (sorry): It’s worth nothing that the great majority of my things (and I think most people’s things) are NOT ST proprietorial. Most of my things are Z-wave. And I think even the ST zigbee stuff is standard Zigbee HA so the majority of my hardware should be movable to another platform. Obviously software side any work I’ve done is out the window… though I have learned quite a bit doing it which should translate… at least in part… to a new system.