The same devices will generally run just fine with a different controller.
There are some device-specific problems, like the current known issue with Sonos, but again the same Sonos devices will run just fine if ST is not in the picture.
If you look at the forum threads with hundreds of messages on scheduling issues you’ll see that many of the problems have to do with backend scheduler issues, completely independent of the devices themselves. Even just changing the mode (no devices at all involved) can fail.
it’s tempting to think that there’s something one group of customers is doing right and another doing wrong, but it appears to be much more random than that. One person even posted screenshots of their account showing a device they’d never seen before named “dining room sensor”–when they don’t even have a dining room! Obviously a platform issue…
Certainly there can occasionally be a bad device. Or a setup error. But the reliability issues reported have mostly been a different kind.
If your system is working well for you, I’m glad to hear it, and I hope it continues for you. But most of those who have unfortunately run into reliability issues have simply been unlucky.