I’m not sure about the very newest generation, but the previous Samsung SmartThings branded devices were made by Centralite, which is the company that makes most zigbee home automation devices in the US market. Including the ones for Lowe’s iris, PEQ, XFINITY home, etc. Of course, any given model could have a problem that others did not.
There have been a lot of reports of problems with the multisensor in particular, and that’s a model which is unique to SmartThings.
One point that has been specifically mentioned by SmartThings staff is that the multisensor seems to start having problems once the battery level goes below 66%.
Anyway, I know there have been a lot of reports in the last six months about problems with the multi sensor. Not so many with the motion sensor, though, but some.
My own problems with the motion sensor are all new in the last few days since the hub update.