I just did a wholesale replacement of Sonos equipment with Chromecast Audio's and a Chromecast Built-in speaker. Couldn't be happier. I had 7 Sonos Connects and 1 Sonos Play 3's. I sold the Connects on eBay for about 70% of what I paid for them over two years ago. It's a testament to Sonos' reputation for build quality that I was able to get that much. I sold the Play 3 to my father-in-law for less than I could've gotten on eBay, but good will is worth a lot.
For reference, the home we moved into had top notch Now Here This in-ceiling speakers already wired in through-out the house. They were using a couple of 12 channel Niles amps and a couple of Elan controllers with built-in wall controllers in all the rooms (all equipment from early 2000's). They took the amps and the controllers upon selling the house, so I simply replaced the amps with identical used ones from eBay. Then I bought the Connects.
This was a pretty sweet system until I bought a Google Home just before Christmas. I went on forums looking for when / if to expect Sonos integration with no clear answers. They announced Amazon Echo integration months ago and still nothing, so I figured we're at least the end of 2017 before they're able to figure it out. It's really not that hard, though. I hacked together a workaround solution over a weekend using Google Home, an old android tablet, tasker, IFTTT, and a program called Macronos. I'm not even a developer or in the IT field, so Sonos could get this done quickly and with much better functionality than I achieved if they really wanted to. I think they're still struggling with their identity and strategy.
I ended up replacing the 7 Sonos Connects with 10 CCA's, and the Play 3 with a Sony SRS-X77. With the Sonos, the speakers in the master closet, master bath, and bedroom were all connected to a single Connect. Each of those now have their own CCA. Same with the dining room and living room. It's not that I'd want to play different music in rooms so close together, but I may not want to play music at all in one or two of the rooms. Having individual CCA's allows me to do that without fiddling with the in-wall volume knobs all the time.
After selling everything, I was able to finance the 10 CCA's and Sony SRS-X77 with an absurd amount of money left over. I went ahead and sprang for 10 CCA Ethernet adapters and a 16 port unmanaged switch just to take any WiFi issues off the table. All of these sit in the wiring closet with easy access to Ethernet, so it just made sense. Given some of the issues I've heard other people having with the music dropping out, I'm glad I did it this way.
I was going to buy 3-4 more Homes as well because I don't think you can full appreciate Google's idea of whole home audio voice control until you try it. If I cast something to the downstairs group of speakers, and then 15 minutes later say "turn it up a little" - with no reference to what to turn up or how much exactly to turn it up - it just works. Try THAT on an Echo and see what happens. Any way, I'm going to wait until after this Nvidia Shield 2 comes out mid-month. I could care less about the gaming box, but Nvidia is also releasing the Nvidia Spot. This is basically a $50 far field mic with a little speaker that connects into the Nvidia Shield, which is also loaded with Google Assistant. 4 Google Homes would cost me $520. For $400, I can get the Shield, which is a top notch Android streamer + 4 of the Spots. Much better deal. Google may come out with their own answer to Amazon Dot between now and then, too.
The CCA's sound great paired with the Now Here This speakers - at least as good as they were with the Sonos Connects - and about as good as you can expect in-ceiling speakers to ever sound. The Sony SRS-X77 is no match for the Play 3, but hey, it's in my daughter's room, it's portable, and it's got Chromecast Built-in, so all in all a good trade-off.