Finished at 98.5%.

Wow, Aria of Sorrow blew me away. While Rondo unquestionably has the best soundtrack, Aria is a phenomenal Metroidvania. The soul system, the abilities, the characters. It doesn't overstay it's welcome (I clocked in just under 6 hours), it never gets repetitive, backtracking never feels like a chore. Everything in this game just clicks. If you like Metroidvanias, I can't recommend AoS enough.