My DCs are both "technically" HFA, but it presents SO differently in both of them as to be incomparable.
Bee (7) is rigid - all about routine. She is unable to bend, has obsessions, and her understanding of social communication is all but naught. She is verbal, but can tend to be "scripted". She exhibits sensory behaviours (currently, she playing in the sink, as it was the only way I could calm her) and has pica - eats non-food items. She is also cognitively impaired and "sticks out". Bee has (and requires) significant support in the classroom, both medically (she has a 1:1 nurse) and educationally (in a class of 6 children, there is a teacher and 2 aides).
DS, comparatively, while he has some odd speech patterns and mild sensory challenges, can "blend in". His cognitive function has been assessed and he is very bright -WISC percentiles in the 99th-, but has splinter skills as well. He struggles with non-verbal communication and has his areas of rigidity, but at 14, is more of an "odd duck" than significantly impaired by his challenges. He has learned coping mechanisms and is becoming a dependable young man. There are days that I actually LOVE his rigidity about rules and routines, as our influence as parents is stronger than the influence of friends, and at the end of the day, he can't be easily swayed by peers. He has ever had any sort of 1:1 support (he did have a period of behavioural intervention and was in a "gifted" withdrawal program in elementary) and is holding his own throughout school, although he does have "tech" support - a computer so he can type all his schoolwork.
Both of them have autistic features that are secondary to their primary mitochondrial disease, but I honestly don't know if their difference is presentation, maturity (there is 7 years between them) or other matters (Bee has had at least 2 strokes - we are not aware of any structural abnormalities in DS's brain). What i do know is they they are who they are, and I can't compare them to one another, let alone other children.