I would test both options and see which one works better. Alexa on an Amazon device tends to perform better than on a Sonos speaker. Personally, I’ve turned off the microphones on all of my Alexa-enabled Sonos speakers because my Echo devices receive commands better and function more smoothly. Plus, Alexa’s voice on my Sonos speakers is way too loud for my ears.

Helpful, thanks.  If anyone else has input, it would be appreciated.

 I have a cube an arc (and lutron lights), and I don’t use either one for voice control to be honest.  I have a Echo show near the seating area.  This is partially because I’m really not much of a fan of using voice to control the TV.  I generally find using a remote much easier and more responsive than voice, but that’s a subjective opinion.  So having an echo that sits close to me for lights and music requests (streaming on the Arc) works just fine.

But as @GuitarSuperstar stated, it’s a good idea to try it out and see what makes sense for you.  When I did my experimentation, I had both turned on with ‘Alexa’ the wake word for the Arc and ‘echo’  for the cube. 

Thanks all, very helpful.