BTW, The good news here is that there’s nothing subtle about the issues that SmartThings has. Maybe it will work perfectly for you. It is pretty easy to install. So if you’re curious, buy it from someplace with a 30 day guarantee and try it with a few Devices that you don’t have to wire or pay anyone else to install and that you can also return in 30 days.
A couple of pocket sockets, some motion sensors, a siren if you’re going to want one, A couple of contact sensors. Install them and use them for two weeks. You’ll know by then whether the system is reliable enough for your purposes.
But understand that if you see weird stuff happening (lights coming on when they shouldn’t, or not coming on when they should, or the siren going off and you’re not being able to disarm it, etc.) that the odds are pretty high that you will continue to see those kinds of problems.
When it comes to security, everybody has their own requirements for peace of mind. I pay extra for a purposebuilt security system with a monthly fee. Like everybody else, I complain that the fee is too high, but I’ve had it for about 10 years and it’s only had two false alarms in that whole time. It works whether the Internet is functioning or not and whether the power is functioning or not. It calls a professional monitoring center who is authorized to call both fire and police. But that’s what I want. It doesn’t mean it’s what you want.
A lot of people are OK just with a system that sends them a text message or a push notification and won’t work if the Internet is down. They just don’t want to pay a monthly fee.
As long as you don’t pay a lot of money for devices you might not want in a month, including installation fees, I don’t see any problem with getting SmartThings and trying it. Just in order to be fair to yourself decide ahead of time what your expectations are for reliability, stability, and ease-of-use, and then judge the system against those standards.