The importance of a "musical subwoofer" will depnend how much you value accurate music reproduction and how low your speakers can go. If your front speakers can only go to 60Hz and you listen to 90% music, then the "musicality" of your subwoofer will be more important.

With that said, I have heard great things about the HSU subs regarding its "musicality". Though it probably isn't as "musical" as subwoofers such as the ACI Maestro (really expensive) or Rocket UFW-10 (doesn't go as deep), from what I have read, the HSU VTF-3 strikes a nice balance between cost and musical performance, without sacrificing the low end extension. These are based on the subjective impression of others, and I can post those links if you are interested.