I have seen numerous posts from people who have and love either unit. My guess is, very few have listened carefully to both, so it's going to be difficult to get this specific feedback.
For streaming, the CXN is controlled by Cambridge's app or a DLNA control-point app; the Bluesound, by a BluOS app. They are mutually exclusive ecosystems. That will affect user experience, not the sound. You might prefer one or the other, but which? Generally speaking, I think BluOS is considered easier to use and better for multiroom playback, while DLNA could be considered more flexible. (When I tried the CXN2 with a generic DLNA control point, it did not work well -- it was fine with its own app.)
If you have a long run of interconnect going to an amp with balanced inputs, balanced outs are worth having. If all your equipment is in one rack, maybe not so much (though still nice).
As to sound, you might have to get the units on trial and find out which one suits your ears better.
For streaming, the CXN is controlled by Cambridge's app or a DLNA control-point app; the Bluesound, by a BluOS app. They are mutually exclusive ecosystems. That will affect user experience, not the sound. You might prefer one or the other, but which? Generally speaking, I think BluOS is considered easier to use and better for multiroom playback, while DLNA could be considered more flexible. (When I tried the CXN2 with a generic DLNA control point, it did not work well -- it was fine with its own app.)
If you have a long run of interconnect going to an amp with balanced inputs, balanced outs are worth having. If all your equipment is in one rack, maybe not so much (though still nice).
As to sound, you might have to get the units on trial and find out which one suits your ears better.