Hello 
I prefer to write in English.
Iâm starting with HA and having the same questions as you, maybe more⌠
For now I donât use google assistant (sometimes to make a call or something like that) so I donât have any problems to pick another assistant.
I bought a Soundlink revolve+ and wanted to buy a echo dot or google mini to put the music from spotify/radios in this speaker.
I want the Assistant to control my sonoffâs (waiting for them), my roborock s50, etc⌠and donât know what to choose 
Did you make more testes with Alexa and did you already tested with GA?
Does Alexa works well with android phone to give instructions? (ex: open the garage door with sonoff, etcâŚ).
Thanks for your help
Ivan
You can use Alexa just fine with Android, either add the widget from the app which you just press and say the command you want minus âAlexaâ or you can set Android to use Alexa instead of GA as the default by whatever means you call it up. Third but not so friendly method is from inside the app itself.
but only if the android version is high enough 
Hi @lucky !
Regarding your questions:
Now Iâm using Alexa to give it a try. Itâs working real well combined with HA. I found âherâ Spanish voice more natural than the one in GA.
Alexa excels for controlling music with my Sonos, I can tell her âAlexa, play Dire Straits on Sonos salonâ and works without issues. However, I do not know about other speaker brands although if they have the feature âworks with Alexaâ I guess itâll work fine.
Again, regarding home control (sonoff, etc), for devices setup to work with HA, works great with both Alexa and GA.
Iâm used to talking to GA on the phone and therefore I havenât tried much Alexa on my mobile, but, when I did, it seemed to work well as Bobby_Nobble says.
Hope this helps! Tell us whenever/whatever you choose, how it is going.