I still can't believe RightStuf licensed Piano. I hope I'm not the only person to have bought the DVDs. Piano is a 10-episode series that seemingly few people watched to the end. I'm not saying Piano is boring, but it's very slice-of-life, not a whole lot happens, and Miu spends most of the series mildly unhappy the way only a young teenage girl can be. So it's a hard sell even if Miu has the second best hair in the history of anime.
I originally watched Piano because of the Ayako Doctrine. The Ayako Doctrine applies to Piano a bit more than it typically does since Kawasumi Ayako (a skilled pianist) not only voices the main character, she also composed the opening theme and presumably plays the piano as Miu.
There's not much else to say about Piano. It is a pleasant little show about family and relationships. Miu doesn't really have her act together, but it's forgivable since she's still a kid. Her greatest challenge during the short series is struggling against the temptation to just give up when things get tough. To that end, she performs much better than say Satou from Welcome to the N.H.K. Beyond that, there's not much drama. You're not going to see anyone bent over a baby grand, for example.
Is Piano still worth watching? Well, I like it. And if you follow the Ayako Doctrine, viewing at least the first two episodes is compulsory. Despite starring Kawasumi Ayako in a piano-based series, there really aren't many similarities to Nodame Cantabile. In fact, there aren't many similarities to very many shows now that I think about it. I suppose you could say that's its main draw: Piano is unique in being so ordinary.