It's good that they've reconsidered or at least broadened their target market. All of their stand alone amps and pre-amps look great.

My customers all seem to use either Spotify or Apple Music. MusicCast isn't a good solution for either, even Amazon might work.
Alot of music downloaded on phones is grayed out and unplayable on MusicCast, thankfully these people aren't familiar with Sonos or this would be much harder to explain.
Neither company is perfect, I would hate to have my customer go over to their brother-in-laws house and have him do something I told him wasn't possible though, like play songs downloaded on his phone or Spotify in more than 1 room.