Overall I think NANA’s main selling point is “realism” and that it’s a pretty realistic look at the Japanese music industry, though dramatized, of course. The characters feel like real people and the relationships, which are really an extension of the characters, almost never go in foreseeable directions. Some intriguing backstory has come to light and I\'m in suspense on several fronts -- I really want to know whether things will turn out okay for these characters.
But at the end of the day, I think Ai Yazawa\'s Paradise Kiss is better, because it is tighter. Nana is full of drama and suspense and heartbreak and really messed up characters, but it tends to drag, especially in the later volumes.