You're not alone... I like her as a character, and as a friend and even as a fuck buddy, but I absolutely don't like her as a girlfriend... she's waaaay too jealous and clingy.Others like her and that is fine, I'm just not a fan of her.
Same goes for Nikki... I just can't deal with that type of people, even in a video game it seems...
And btw, I really don't like that you have to be both on Alexis & Nikki's paths to get the most of Valeria's scenes... really sucks for me =(