I have two Cambridge Audio players - an Edge and the model that preceded the CXN (StreamMagic 2). The firmware is updated regularly, so I expect they all share it. They both work really well. I use Roon, and the roon integration is seamless. They also use airplay and Chromecast protocols, although they sometimes behave strangely with Chromecast grouping. I don’t know if that is Roon or the device itself. Oddly, it is a google device that typically drops, not the Edge.
Playing music directly from file storage on the Cambridge devices is very tedious. You are much better off running a light music server with your music storage (I used MinimServer, because you can structure the music server with the tags in the library).
Happy to answer any other questions, but I’m a fan. Guests can use the Spotify/airplay/chromecast/tidal features easily, and I have seamless Roon integration.
Now, I also have a system with A Raspberry Pi running ROPIEEE (formerly ROPIEEXL). That also emulates airplay, and you *can* use digital volume in Roon, although you might not want to. And it costs less than $100 plus about 20 minutes of fiddling and configuring.
AND I have a WiiM, which is also pretty cheap, has a DAC like the CXN, and does Chromecast, Spotify, Tidal, and Roon. It’s had a few buggy moments (it did a hard reset on its own a few days ago) but is also a bargain. No screen.