I really like the rounder look of the classic series. Afterwards they started getting too sharp and serious, by the Boo Saga he relaxed but it was too much.
Although he doesn't draw anymore, the drafts he does for the characters are the definitive look for me.
AT also did artwork for the Kanzeban releases and the Daizenshuu right? I think this lost era of the 2000s is a bit weird looking, but it's probably the coloring trying to add some lighting I'm not used to seeing.