At the intersection of autism and OCD, by Cynthia Kim (Musings of an Aspie blog). Very interesting article exploring which of her traits are due to OCD, which are due to autism, and how to tell the difference.
Perhaps one way to differentiate is by how the thing makes me feel. OCD traits are characterized as anxiety-inducing and unwanted. For [autistic traits], the outcome is pleasing, the process soothing.