Lucy Liu, Angelina are both beautiful women in my mind

I think it is not about Americans and Chinese. Even Chinese has different views on beauty. Overall if a lady is beautiful I would say both American and Chinese would think she is beautiful. Americans could care the looks a little less than Chinese ( A little less not much less). They factor in common interest, chemistry and other stuff too. 15 years age difference is too much. if the age difference is that high the older one must be rich. I personally will never go beyond 5 year older or younger.
Having said that there were more challange building relationships with Americans than with Chinese. Culture difference plays a role.
Most Chinese girls prefer tall and handsome Americans.
But tall and handsome Americans mostly are not as successful and compromising as average Chinese men. Most Chinese people know how to manage finance well but Americans dont. That set some future conflict in the marriage. So it totally depends on what you want.