Sonus One vs New Echo Plus

Either, whichever you prefer. They both work.

You say as the "hub." If by hub, you mean that you're looking for something that will communicate with other smarthome devices such as lights, plugs, switches, locks, etc., where each uses a propriety hub like the Philips Hue hub or Zigbee, then you want the Echo Plus. So for example, if you want to control Philips Hue light bulbs, with the Echo Plus, you just need to buy the bulbs. With the Sonos One, you would need to also get a separate Philips hub in order to control the lights. On the other hand, some devices don't require a hub to work with Alexa. If you get, say a Belkin Wemo switch, no hub would be needed, so it will work with either the Sonos One, Echo Plus or even the regular Echo or Dot. You should research the devices you want to control with Alexa and decide what's most efficient for you. With that said, personally I think the main reason for the Sonos One is sound quality, which is why you're paying a premium. The Alexa experience on the Sonos still needs work, but if that's more important to you, then you should get an Amazon Echo.

Thanks for you detailed response - I am mainly looking for the sound quality and inter connectivity with other speakers so I can listen to music in many rooms. I can manage through the growing pains with Alexa on Sonus as they continue to work through the application.