The Hi-Fi Plus probably has a wider appeal than the Cam Plus, particularly if you use your phone as your main music player, but it's still quite expensive. It adds a palpable boost to the overall soundscape, widening the range of sounds you hear as well as giving the bass a bit more oomph, but unless you have a library full of high-res audio tracks, the difference it makes to ordinary music isn't going to be quite so noticeable. Yes, it sounds better, but I wouldn't pay £150 for the privilege