if nothing else, it kept me so very interested. the entire concept, the characters, (especially Ito! he was incredibly interesting and such a good character) the situations... the art... the psychology behind everything, the homunculi... it flies by without using too many or too few words. yamamoto uses his characters a lot to tell the story, and not just words, which was very pleasant.
now, my only complaint is that the story kind of plateaued somewhere in the middle... and never came back down. i felt like it was a roller coaster that built up and built up and built up and... never amounted to anything really. that's only my humble opinion though. the end was a little muddled also... i was kinda like... hmm... hmm? but it is ambiguous and goes along with the psychological theme left to interpretation by the readers. can't blame him for that - plus it fit the whole character. it left me wanting more, though, more answers and more understanding. i might need to read it again to seek that out, but we'll probably just have to fill the holes with our own speculations.
oh and another complaint, sorry - it's just really not that realistic at points... not just the homunculi, but like others have mentioned, the other character's reactions, some of the situations... it just left me a little unsure of the story. it more than made up for it, however, in other parts of the story.
the only thing i'm really, really confused on is the serial killer category...? maybe i missed something really big?! haha...
anyways, it wasn't all that twisted and horrific and gross, it was a LOT more heavy on the psychological, so if you have such reservations i'd give it a try. heck, if you're at all interested in stories that weave theories and take you on a page turning adventure (ok, not literally, more a psychological adventure mind you - he doesn't travel too far haha), give it a try!!