I will answer from my own experience. As background, I am a white male, 42 years old, educated (MBA), from a middle class Midwest traditional family, great career up to this point and a business owner. I have a networth in excess of $2M (I would say how much in excess) and I would say a 7+ on the looks scale (blond hair, blue eyes, 6', etc). I had my pick of women pretty much my whole life and I mainly dated white women through to my current wife.
Looking back on it, I think I would sum up the situation as follows:
1.) Western women are fat and getting fatter. Sorry, but this is unappealing to me and having a good sex life is important for any relationship to continue. Once you stop screwing, you are headed for divorce. Seriously, a woman's attractiveness is 50%+ weight related. Stop eating so much and hit the gym for cardio (no weight training)
2.) Asian women have a more traditionally feminine shape. This includes slender arms and legs (which tend to be hairless), better quality hair, slender waists, etc. Now, there are some buff crossfit Asian girls and I don't find them to be attractive because they are too manly. I have no desire to sleep with a woman that looks like a dude.
3.) One of the biggest joys for any man is caring for his woman and having her experience new things with him (even if it is not new to you). Like taking a girl to Paris for the first time. Asian women love and appreciate these kinds of things. White women, by and large, don't because they want to be an equal.
4.) # of prior sexual partners. Asian (decent ones) tended to come from more traditional backgrounds so you can find a girl 25-30 that has not slept with over 10 guys. That is nearly impossible to find in a Western woman. Even ignoring whatever STD is lurking in her, I really don't want a woman on my arm that has slept with half the town and has a vagina looser than a magician's sleeve.
5.) Western women have selected themselves out of the sexual market place by overrating their qualities. I don't care how much a woman makes, where she works, what family she is from, etc. because no self-respecting man wants to be reliant on the women as the breadwinner. So, woman are maxing attributes that are meaningless while minimizing those that will actually attract a mate.
6.) Women like Danni - nothing more needs to be said.
I find that Asians get a bad name based on the money hungry types in poor Asian countries dating old, fat white dudes. This is a small fraction of the population of those countries.