OK, I have to ask, because I seriously DON'T GET IT:
What's with the Amber-hate? I know Amber's not perfect, but at least she's genuinely trying to help people - and it seems like all she gets for her trouble is a zillion readers despising her.
A lot of reasons. Partially it's because this is a villain protagonist piece, so we naturally sympathize more with Gail than with Amber because we're seeing things from her point of view. Partially it's that Gail is a more fun character. It's also that while Amber is technically the good guy, she's not a particularly pleasant person -- she comes across as someone who is "good" because they have never had any reason to be otherwise.
Basically, there are two formulas for creating heroes: either something really bad happens to them (usually a dead parent or parental figure -- The Call Knows Where You Live is the TV Tropes title), or they become heroes for no particular reason (e.g. Booster Gold wanting fame, Iron Man more or less because he could), and then have to grow into their hero philosophies. The latter typically has a much longer period of figuring out how to define themselves as a hero, and consequently can be more difficult to present to a reader. Booster Gold is frequently more of a comedic character because of this -- basically, we can't feel sorry for him, so we have to like him for some other reason.
In summary, as of this point, we have very little reason to like Amber. We have seen that she's spoiled, self-centered, small-minded, shallow, rarely acts on her own, rarely listens to good advice, and (perhaps most importantly) is knowingly and willingly cruel towards characters that we *do* like. Once she gets her act together as a hero, reader reactions will change.
At this point, she's sort of in the same place as Peter Parker post-Spider Bite, pre-Uncle Ben's death. There's a reason Uncle Ben died in the first issue -- Stan Lee *knew* that people wouldn't like that interim Peter, so he firmly establishes Hero!Peter by the end of that issue.
Um...apologies for the tl;dr -- I just really like this stuff.
Understandable, but we already HAVE seen Amber act heroically - stopping the hostage taker earlier, and her current confrontation with Gail (which is even more heroic when you consider Gail CAN murder her, has shown herself to be perfectly willing to, and has defeated her in the past).
Aside from all the good points that tekla made, Amber's being shown as not much more than a nuisance at the moment. Sure, she's the hero, but Gail is the main character, and she's developing her powers and prowess as a villain rather rapidly in comparison. Amber has a lot of flaws, and thus having less motivation for her role than Gail does, she doesn't have the skills and such to compete. So while everyone realizes that she's the good guy, she's more of the irritating pebble in the shoe type at the moment. Gail does her thing, and Amber shows up to slow her down for a chapter or two, until Gail emerges one step ahead as always. Not sure when Amiko will have Amber on even ground as Gail, but when she can actually rival the protagonist, she'll be seen as that much better of a character.
Oh, and not sure why people get upset over the Amber-hate. If readers don't like her, that means people are paying close enough attention to her character to form an opinion on her. (I don't know about the rest of you, but I'd rather have someone have reasons to hate my character, than to like said character just because.)