I have no experience of Alexa, only Google Mini's. They seem to work well, but some times it does get it wrong, likely because I have no teeth, seems to work OK for my wife. It does show when contact is lost, the icon is greyed out, and shows blue when switched on, and the voice will also report when it can't do as asked.
But it can make mistakes, in the early days I would say hey google turn off, when listening to radio 4 extra, and it would reply turning off 5 switches and all the lights would go out, hey google turn lights back on, got I don't know how to do that yet. However now we have got use to it, I realise it did not know the switches were lights, and had I asked it to turn on 5 switches likely it would have worked.
My landing light has two sections centre and outer, the command hey google turn on/off landing light turns them all on/off, but switch outer or switch inner will switch on inner or outer lights.
So in the main down to the names you have used, turn on linda's bedroom works different lights to turn on linda's bedroom lights, not googles fault, that's my fault in the names I have selected.
I can pair the Nest Mini's so can have stereo, I am only using the Mini's the larger version is likely more powerful, the early mini's with USB power don't seem to hear us as well as latter ones with jack plugs, there is a switch to turn off the microphone, although that makes them harder to use.
Biggest problem is when asking it questions it some times sends the link to my tablet, so wife will ask hey google who were the kings of England, and it will arrive on my tablet as well as voice report.
I will admit they were not bought to automate the house, where we live there is no FM radio reception so they were got to listen to radio with, I think we have about 8 of them, so works in every room. Although not one in the hall, others in the house do hear the commands.
With three floors the broadcast works well, no need to shout my wife.