Alright, I’m gonna answer your question in two points:
1) Dumping the ‘Nice Guy’: She is right to do so. The reason is that most of these ‘nice guys’ are NOT nice because they want to be nice, or because they are nice. They are nice, first because of FEAR of dissatisfying, bothering or displeasing the woman. Second, because of the NEED to achieve their desired aim: make out, have sex or start a relationship with the woman. So here you have it: a combination of a coward who is NEEDY. This is the ugliest and most pathetic form of character, who would turn off the most desperate of women. Heck, even I would wanna avoid such a guy. He’s got no balls and he’s all about pleasing people. Like a mobile charity organization. Eww.
2) Going with the as*hole: I will not defend that. Women who dump the nice guy and go after as*holes are stupid and immature. The notion that “assholes are exciting” and “assholes are a challenge” is even more stupid. Just because he is ‘more exciting’ it does not mean he is good for a healthy relationship. He may not even be good for friendship. And giving him more attention and affection that other ‘non-as*holic’ guys only pulls her down to his level.
That being said, what you need to do is be fair with women. Any woman. Be fair to her and yourself. If she looks good, compliment her as much. But she needs to look VERY good to deserve it. If she says something stupid, face her with it. If she does a mistake, corner her with it. Take a stand. Show her you’re pissed just like you show her you’re happy to see her. If she’s playing hard to get, play harder. If she doesn’t spare time for you, do NOT spare time for her. Move on. There are plenty of women out there who may deserve the time and effort you’re gonna give. Always remember there are tons of other guys approaching her everyday. What’s gonna make you different? Being genuine.