I started PH when it first got scanlated, there were reasons why I wanted to try it, and it was worth it all. Although it took a long time and a lot of intentional drops (to spam read instead of waiting slowly for a single chapter)...including my laziness, I was finally in the mood to catch up to the end. Sometimes the series might test your patience but so to say, there is merit.
The entire series doesn't rush itself, it takes its' time to develop wonderfully, which I want to say, this is not a self-butchering series. Love, tragedy, pschological, light humor, philosophy, and action, it's all there including the darkness and my favorite theme, Alice in Wonderland. It was the easiest bait for me to give into this series along with the artwork that I end up loving.
My major credit and utmost respect for the entire series is that each chapter or every few chapters, you get a new development and plot twists, and the most important factor, is the foreshadowing (includes plot twists).
Despite the patience-testing occasionally, after certain major events, bits by bits, everything fits in but not completely in a sense. It draws you back into recalling the various hints and moments that might not have seemed too important but ends up being crucial. This was the sensation that I've always loved because it rattles your mind only to throw you off sometimes.
Every character has a role or a connection to every factor, if not, it relates to the story to some extent or beyond. They blend well, they don't totally miraculously appear from nowhere whenever a new character is introduced.
I don't think I've ever disliked any characters after finishing Pandora Hearts, in fact I loved them to a certain extent even if I was previously annoyed before. Maybe it was due to the anime, but it felt much easier to read, imagining how the characters' voices from the anime did its charm sometimes. Not to mention once you've seen their backgrounds, you can't really dislike any either, each character has their own philosophy as humans we are as well.
Nonetheless, I grew fond of most characters, the theme being an instant bait for me, and how the series advances slowly but with regards as it is a mystery as well... I believe Mochizuki executed everything splendidly befitting of it's contents and what it is.
Honestly, I wish for a Pandora Hearts anime reboot so it can adapt everything that the anime couldn't have done as it was still progressing at that time. Pandora Hearts is a series that I love, for the set up and the development that it was underestimated but regardless, it is beautiful and spectacular.