I kind of look at them both through the lens of noir. Victoria is the femme fatale who exudes sex appeal and probably gets you into the mess. You know full well she's bad news, but you want her anyway. And she's probably going to betray you at least once, and while she may eventually claim she's fallen in love with you, you'll never be entirely sure whether or not you can believe her, or if she's just setting you up for another fall. And maybe you'll be better off ditching her even if you do believe her. Because that's a bad road with no happily ever after at the end.
But Katie's the good girl who loves you deep down, and would do anything for you, and you'd totally be happy together - yet you're probably going to ignore her and break her heart anyway. Because on some level, you don't believe you deserve her, and you think she can do better. You're a broken, broken man, and you're almost certainly going to come to a bad end. Because that's the sort of man who winds up a film noir private detective (which is basically what you are in the this game, cyberpunk future and crazy mercenary skills aside).