I think when they change the official diagnostic criteria next year, they are planning to drop these different categories, and just stick to the single description "autism spectrum condition"... a lot of the differences between these categories were fairly minor, and were often applied according to individual psychiatrists' personal opinions.
For instance, according to the old DSM-IV criteria, a research study showed only one in a few thousand people exactly fitted the description for Asperger, therefore a lot of people got given other diagnoses. Nowadays, specialists use broader criteria, and so the rate is about one in two hundred.
So I guess what I'm saying is that it's mostly just words, and truth be told there are probably as many different ways of being autistic as there are autistic people.