I personally saw Harmony of Dissonance, and Aria of Sorrow to be equivalent to each other. Aria's musical composition was really lacking, which Harmony, despite using an outdated system for its tracks, came up with very rich, and quite fitting music for its atmosphere. The only peeve I have is Juste's sprite, and that's about it.
They each have their own charms, but Harmony makes some risky decisions that it carried out quite well. It's certain as open for exploration as it's predecessor, Symphony of the Night. That, and it has a ton of easter eggs. Aria's far more linear in that matter.
For whoever said HoD is nothing more than a turd with pretty backgrounds, it would have been nicer if you at least explained why that is.