My opinion on the nature of Aikido students vs. anyone else is:
1. They have a stronger interest in resolving issues without big confrontations and blending.
2. The need to participate in a competitive activity is less.
3. A more cerebal approach to martial arts (perhaps this has to do with average ages?)
4. Greater interest in the moral and spiritual aspects of martial arts and consequently life.
5. More welcoming to strangers and newcomers
I form my opinions based on my own experiences and stories I am told by friends and other students.
There are examples of Aikido students which run counter to what I have said but overall I feel the above is true.
I think anyone who participates in a Martial Art of any kind have some different charateristics than people who don't. In addition because the biggest difference between Aikido and other martial arts is the moral approach to defense and since the Aikido Student has chosen Aikido over other arts then there must be some difference in that student.
Again there wil be examples of students who start Aikido for other reasons for example lack of another martial art available to them but I believe my opinion will be valid for the majority especially those who stay with Aikido for some time.