I like them both, really. I like it when the director allows the individual styles of their animators to come through. Imaishi and Yuasa are the masters of this.
I've also got a serious hard on for Yasunori Miyazawa. He did the ending part of Dead Leaves with the giant space grub. He's developed a really interesting way of drawing his FX - different even from Imaishi, who everyone seems to be copying at the moment. Shinya Ohira is a another current FX guy I like.