I have a Sonos Connect in one of my systems, where I use it merely as a streamer and output the signal to a Meridian Director DAC. The limitation you will find is that the Connect cannot resolve beyond 16/44.1k - higher res files will not play at all. However, I stream Tidal and Qobuz (CD level) and it sounds as good, if not better, than my Meridian CD player. I've not spent much time listening through the Connect's internal DAC, so I cannot comment on that.
That said, if you are already using the Sonos environment, give it a try. You can always add an external DAC down the road, but I wouldn't invest too much. You'll still be limited to CD level sound, and the Connect's life span may be limited since Sonos will no longer update it.