I think there is nothing wrong with men dating older women, after all, being in this set-up is a mutual decision. However, this type of relationship may face some troubles due to issues on maturity and generation gap (if in case the gap is really huge). I have a friend who is dating a guy younger than her. She told me that there are times when their humor won't meet each other. That she had to explain to him that she was just joking or being sarcastic about certain things, and vice versa. Women are often viewed to be more mature than men; hence, in their case, when it comes to some instances requiring major decision, she often takes the lead. Although such is the case, both of them do embrace their differences just like any couple. They also get to learn a lot from each other, as they both have different perspectives in life.
One thing that kind of makes them worry is how and what other people will think about their relationship. Sure they get a lot of negative opinions, and they do admit that such words affect them and their relationship. But what I liked about both of them is that they are very vocal about their feelings and how they would want their relationship to proceed.