I also enjoy the convenience of having music on a hard drive to play hour long playlists on my squeezebox, though, as I have said, not up to par (to me) for critical listening. (I did come up with an excellent work-around, though-I have an Alesis Masterlink CD burner and put nice compilations together on MoFi Gold CDR's and play them on my Esoteric. 70 minutes or so of pure bliss - close, but not totally the squeezebox convenience, albeit much better sound).
As for the difference(s) between the Ayre Ax-5e & Ax-7e, I thought they were close at first, but after a few hours of listening, on redbook, I found the 7 to be a bit leaner overall, a bit more forward sounding than the 5, not as much punch or dynamic and the soundstage was petty much as wide, but no where near as deep. On SACD, the difference was even more dramatic. The 5 had much, much more overall resoultion. The 7 played SACD's like very well recorded Redbooks but the 5 delivered more music, more of the experience. Cymbals had more air around them and the decay was very realistic on the 5; on the 7, it didn't have as much space, and was a bit abrupt. Vocals on the 5 were smooth and lifelike, while on the 7, there was a hint of symbilence (please excuse spelling) and I didn't feel the presence of the singer as I did with the 5. The 7 did mask inferior recordings better than the 5, but that's a trait I find in less revealing gear, and, to me, I need to hear everything that was recorded-good, or bad.
The Esoteric (X03-SE) was even better than the 5, with greater dynamics, deeper soundstage greater air and presence and the retrieval of low level detail blew my mind. On Jacintha's SACD, Goes To Hollywood, on Que Sera Sera, on the opening acordian, you can hear the acordinaists fingers on the keys, and the sound the keys make when they are released. On the 7, you can barely recognize what it is; on the 5, you hear it distinctively but on the Esoteric, it becomes part of the performance. It actually adds to the experience and makes the little hairs stand up on my neck. The resolution is absolutely amazing.