If you liked the Betterman anime, the Anime-Planet community thinks you'd like:
In a futuristic world almost barren of life, mankind is confined to mechanized domed cities where A.I.’s control all aspects of life. In this world, humans are no longer born, they are manufactured in a production line; and alongside them live androids known as autoreivs. Within one of these domed sanctuaries named Romdeau lives Re-l Mayer, one of a few citizens who aren’t entirely prevented from thinking. Her grandfather's prominent position and the affection of the scientist Daedalus have left her more free will than is normally allowed, but Re-l has started to question the sanctity of the city and the citizens' perfect way of life. With mysterious beings known as proxies causing havoc and a man named Vincent causing great influence on her life, Re-l must travel outside of the city to find the answers she seeks and discover the mystery behind "the awakening".
The mystery of Betterman simply eats at you to figure out the meaning of everything. You are drawn in by the moments of overwhelming paranoia, the lingering notions of why has Algernon come into existance, why and how does Lamia transform, what does he have to do with Hinoki, and what do they all have to do with the caves in India?
While Ergo Proxy doesn't specifically deal exclusively with human evolution like Betterman does, it does have just as many things that hook you into it that are on the same intellectual level, such as references to Greek Mythology and Philosophy, Genetics, Literature, and Sociology. You can't help but watch to find out the answers to Re-L's life, who exactly Vincent is, who and what the Proxies are, what happened to Earth, and why the Cogito virus exists.
Maebara Keiichi, an ordinary high-school boy, has transferred to a new school in Hinamizawa, a small rural village. At the outset everything seems peaceful and Keiichi becomes friends with a nice group of schoolgirls with whom he spends many idle summer afternoons. Suddenly violence encroaches upon the blissful peace of the village and Keiichi becomes entangled in an endless cycle of fear and death. The inconsistent, but inevitable horrors of Hinamizawa are told and retold becoming an endless and inescapable nightmare of insanity. Will it end even if the mystery of Hinamizawa is solved?
Betterman and Higurashi keep your mind moving and trying to figure out the plot, while slowly giving more and more hints along the way. Both shows also deal with a sickness that causes the victim to act violently under certain conditions. They are thrilling shows and have a great scare factor.
Trust me when I say that Betterman and Higurashi no Naku Koro ni are great veiws, and I'm sure that if you liked one you'll like the other as well.