I'll be very brief. 1. The worst: a) Excessive and repetitive CGI, poor-quality animation. Paradoxically, the characters were re-drawn better than in 1st season and ameliorated the opening. Lowwer cost in production? b) They quit focus on one character and gave it to another (that wasn't in the opening, I anticipated the story for nothing, I guess I'll read the manga). c) I felt more tachycardic in the 1st season. 2. The good parts were: a) Classical music, you have to love it or hate it. Maybe they over-repeated thesame pieces again and again like in a real Piano Contest.
b) It has a couple of dark sub-plots for two of the secondary characters. Also, they teach you about how to deal with your personal issues, philosophy of life, etc.