I'm currently seeing a doctor for my OCD. I could easily fit most of the AS criteria, and really can't find any major differences between myself and you guys. However, I can only speak for myself.
OCD is an anxiety disorder. It's characterized by obsessive thoughts (unwanted) and compulsive behaviour (to release anxiety).
For a person with OCD, their obsessions are unwanted.
I have both wanted and unwanted obsessions. For instance, If I spend all my time reading about a specific topic, this is voluntary. If I feel the need to walk through a doorway 5 or 10 times because I belive something will happen if I don't, this is involuntary.
I find social interaction very difficult. Routine change. Decision making (can't choose between the possibilities. this goes for sarcasm as well;) Motor clumsiness. sensory issues.
It's possible to have some autistic traits, even though you can't be diagnosed.