probably Blue Exorcist :) though, to be honest, I haven't read very much of the manga, but watched the anime. Same with Blood Lad. The manga keeps calling my name loudly at book stores though :) maybe I'll answer it next time.
I always prefer to have the manga instead of reading them online. I love having a physical copy so that I can read them whenever I want and for their aesthetic value. I hope my local bookshop has them. If not I'm sure I can buy them online.