Back in March I had received my new Port to replace one of my Connects. When I received the port, I did a sound test of it and my connect still running S1. The sound was excellent, very detailed and full. After a couple of days, I went ahead and installed the S2 operating system. 
I have been streaming most of my music these days and I’ve gone from being happy to almost regret as far as sound quality. I have S2 compatible Connect that I ended up switching from the new port, and I have found the Connect sounds a tad better, but not like it did prior to switching to S2. 
 I have always run my connect through a hybrid Dac that goes into my system, and I just find the sound quality is really compressed sounding, the low end is lackluster and the highs are not near as detailed as they were before I ever started to upgrade due to another connect no longer being supported. Basically the sound was night and day from my original Sonos that I’ve run for the last 7 years. I also did a trial of Qubuz to test out the “higher res” sound and actually I found that it really is only CD quality through the Sonos and Spotify actually sounds better. 
 

I hope maybe in the future Sonos will figure out an update to upgrade the sound quality. I have found the sound quality to be worse on all my other 9 Sonos products.