When I read manga the first thing i see is the art, and i want to know wich one u think is the best, for me it might be someone like oh great! or boichi
Oh!Great will be on my top list after he actually learns to be consistent in his character designs. Sameface a la [insert mangaka here] is somewhat forgivable as long as I can identify which character is which.
Best art methinks still Mori Kaoru and Inoue Takehiko.