I do not think he deserve all the hate. He really did his best to remedy his own mistakes and become a better person. However, there is always someone who, even after years, is convinced that his status quo must be that of an asshole.
Ultimates has certainly helped bring the idea that Pym is a loser and so Bendis with Avengers Disassembled and Millar Civil war, where Pym is terribly unlikable.
Pym was great in West Coast Avengers.