I would say the choice really comes down to interface and flexibility. There is some simplicity in a multi zone matrix server, one app, one box, but generally a little pricier and commits you to the platform. Sonos is great — I’ve used it at my father in laws and have to say, it’s really rock solid connecting to it and controlling the zones. Personally, I use chromecast audio devices connected to external DACs with optical cables to dumb amps (Emotiva BasX 5 and 7 channels). I went this route because it was a lower cost per zone and I only listen to Spotify Premium, so casting to the devices was a good solution and it enabled me to control the quality (spend however much you want on a DAC or amp). If you have a large library of music, you can use a PC or NAS with something like Plex to cast the music to the chromecast.
The only complaint I have with the chromecast setup is that your WiFi needs to be rock solid. I have a few dead zones and it’s frustrating to try to control the music in those. Otherwise, we’re loving the setup and it’s easy enough for my wife or 7 yr old to use. I also prefer that my equipment is not locked in — outside of the $35 dongle and cheap DACs I am currently using, I can always move the amps to a home theatre setup and I do not feel like I put a bunch of money into something that will be obsolete.
There are really a lot of options. With the research I did, it comes down to audio quality in the source and in the transmission, and overall usability in the interface. The prices do vary quite a bit and setup and overall maintenance might vary if you go custom install like Control4.
Main 7.1 HT: Dali Zensor (7s, Vokal, and 1s), Emotiva E2s, HSU ULS-15 MK2, Emotiva BasX preamp/amps (MC-700, A-300, A-500)
Kid’s 5.1 HT: Dali Oberon (5s, Vokal), RSL C34Es, HSU VTF-2 MK5, Denon X2400H
7-Zone CCA/Spotify WHA: Paradigm (E-80Rs x6, P-80SM), Def Tech AW6500s, Polk MC-80, Emotiva BasX amps (A-700, A-500), FiiO D3 DACs