I own one, I really like the 4000s, but the 5000 has wireless built in, not really needed for a sideline instrument solo that you can plug direct into an amp, but a feature some like. The touch sensitve keys take some time to get used to, so let the student have plenty of time on it before you start rehearsal. The octave rollers are really nice to switch ocatves but require a lot of practice to not just jump ocatves. Also look up set up videos on how to set up the breath sensitivity to aide with the ability to do dynamics properly. Note they do not come with a case usually, so buy a protect soprano casse, as well. I recommend getting the patchman sounds as well. I have not had any time to look at the solo, but from the short time I have it looks promising as a good option as well. https://www.patchmanmusic.com/akai.html