I'm talking more about artist ability than what they chose to draw lol. I personally like how Akitsuki Itsuki draws the eyes on his characters -- it looks so simple, but they are so expressive and unique.
Karma Tatsuro, especially his older works. Also Yoshiyuki Nishi and Ikuhana Niiro. Though I doubt they actually are, I like the more hand drawn pen and paper sketch looking styles.