I just moved into a new house where the previous owner left behind (installed) a bunch of Nest Protect smoke alarms. I looked into putting them on my own account, but found two really lame issues:

1) They don't support GSuite accounts, and Google Home doesn't support linking other accounts when your main account is a GSuite account, and

2) They've shut down all API access to them (people still on old Nest accounts are grandfathered in... for now), so even if I did manage to set it up on a separate non-GSuite Google account, I wouldn't be able to monitor them with openHAB.

I do like them, especially how it warns vocally shortly before it's about to go off, so I can preemptively temp-disable it before it deafens everyone just because I'm cooking and forgot to turn the hood fan on. And the motion-activated nightlight is perfect (there's one in my bedroom right near the entrance to the bathroom). But Google's product support strategy here really makes me uncomfortable, so I'll probably end up replacing them.