I bought one of those for my gf because I wanted to see if it was any good.

Quick review.

iOS users have to use their spotify app which is lousy.

Google Play users can cast to it, thankfully.

Major positive point is that it uses wifi and supports casting from Google Play. But for my gf who uses iphone she hates it.

Overall we prefer the Marshall bluetooth speakers over Sonos because in an apartment there's rarely a need for wifi casting music.

Edit: Chromecast audio is also a viable alternative. Based on how well my regular Chromecast (video) works for me I assume the audio one is as good.