Yeah, I'm sorry. If you're preferring Pluto over 20th Century Boys in the 2009 Urasawa sweepstakes, you're something of a tool. Pluto is pompous, derivative, overwrought, joyless, and telegraphs like nobody's business. 20th Century Boys, on the other hand, is rooted, spritely, active, agile, and cleverly telegraphed a complete and utter lie so convincingly that I had been prepared to be disappointed in advance of the development - and then was blown away when Urasawa yanked it all out from under us with an old-fashioned narrative time-jump.
Oh, and that critic pulled the usual boner of confusing "dark and gritty" for "mature". Maturity is a mind-set, a willingness to recognize the childishness of the artifacts of childhood, and to set them aside as illusions. 20th Century Boys is about the illusions of childhood, and the complex interaction of nostalgia with illusions, but the villain of the story is a monster of nostalgia, and childish fantasies are the weapons with which he corrupts, subverts, and conquers.
Pluto, on the other hand, is a glossy re-write of the old Tezuka chestnut, with a lot of pious anti-war posturing and tedious, unoriginal rehashing of the hoary "Androids Dreaming of Electric Sheep" theme, with a heavy ladling of Three Laws of Robotics utopian cheese. There was a couple solid chapters at the beginning about a British robot with survivor's guilt, but everything since then has been running in place, with a very annoying detour through Fantastic Racism and an expy anti-robotic sort of Klu Klux Klan organization, complete with white hoods. Bah.