I'd disagree with the whole 'Ivy is the Evil Queen' bullshit.
She isn't this "EVIL" person that most of the narrow, small minded simpletons try to make her out to be. Though the comparison between her and Jessica is actually spot on in some forms.
With Ivy: She's freespirited, enjoys casual sex, not looking for a relationship and may seem against it though in all likely hood her reasoning is probably more solely on the fact that she simply had a bad experience with a relationship and doesn't want to be hurt by it, or truly does simply believe that casual sex is all well and good. Or it is possible that she simply hasn't found the right partner in her that loves her for her and supports her/challenges her in a way that isn't in the money sense but more so her life. And while there are some that see her "influence" on Holly as "EVIL, MANIPULATING, Etc.", I would argue it's more so challenge Holly to break out of her shell and open up with her life. Try things that she normally wouldn't do. To which, is entirely OPTIONAL and we, as Lena, have the option to either encourage it or temper it abit.
With Jessica-Ivy: Their more similar in terms of their styles, atleast from the start. Both are/were sexually inclined, using sex to get their way/pay. But depending on which version of Jess there is, thats where the similarity really ends.