Not technically a bootleg, this minifigure is not a direct rip-off from any existing LEGO set. The design may have been pulled from a video game or a custom, but I am not sure. Regardless, you won't find this guy in physical form from any other source than those crazy Chinese BootLEGOers!
And while I'm no Ant-Man afficionado, I'm pretty sure if LEGO ever does make Ant-Man they won't go with this comic version and instead will go with the upcoming movie version. That being the case, I am glad to have the goofy comicbook version, which may very well be the only version we ever see!
As for quality, I've said it before and I'll say it again: Sheng Yuan stuff is all pretty great. Ant-Man is one step under official LEGO, which isn't to say he has any real flaws at all. Just that LEGO set the bar pretty high.
His helmet is incredible, his torso has design on both front and back, and he's a great representation of the classic comic Ant-Man. His face only has one (wall-eyed) expression, but that's enough since the helmet covers most of it anyways. The two spider friends are a fun addition too. All that for less than a buck (when you buy him as part of a set of eight figures) with free shipping from eBay - how can anyone go wrong adding this diminutive dude to their collection?