Deadman Wonderland are, without a doubt, a great manga of all time.
It mus be read and re-read for those who really appreciates all sort of things that can be found in a great story: gore, love, nice characters, plot twists, nice quotes and a wonderful philosophy.
The art just fits so weel, it's incredible.
The anime for the manga is good as well, but something is missing, wich is the last arch. I would say that the last arch on the manga has a big plot twist, and this makes the manga so great, so solid, you can barely hold your tears, and I'm serious.
If you like good art style, but, most important, a good story and a great character development, this manga is for you.
Read it.