Technical aspect is top notch, probably the best I've seen so far. Main issue I have with that series is lack of Japanese influence. Most Japanese manga anime have something in common. There is always some greater discussion going on in the background of main story. Humanity vs nature, who is human who is not, what means to be human, relations between characters, lots of emotions going on, many layers like that. Gay stuff, but I like it and it is one of the main reasons why I read Japanese comics and watch their shows. You're rarely going to see any of that in American produced comics and shows. None of that in Hellsing, very barren, like they've made fun show for gaijin simpletons.
Don't understand why no one has made Eden: It's an Endless World into an anime? One of the best manga I've read, on par with original Alita, Monster and I am a Hero.