I just read the A+ manual (forgot I had one) and I'm afraid they did mention that SQ will be affected with iTunes running along side A+. So i guess we should stay clear of iTunes.
On the topic of using remote, I accidentally found out that I could use my mobile to control Spotify that's playing on my Mac. Shoot me but I actually find Spotify streaming at extreme quality almost as good as some 16 bit lossless files in terms of soundstage separation etc. Although I must admit the Concero has a big part to do with that.