no one can truly tell you first hand what the differences would be like as autistics and non-autistics only have their own dreams. any comparison you get is going to be made up of half second hand information.
my non-autistic dreams take many forms. it could be like an entire scripted movie, or it may just be disjointed images. at least thats how i remember them upon waking. i dream in both first and third person, and one dream may cover both modes or switch back and forth during the dream. sometimes they are fantastical and highly imaginative, other times so normal and realistic that i wake up and can barely tell the difference between the dream and reality. ive had dreams where people from my past that i literally havent even thought of in a decade are the prime characters, and its really common in my dreams for people to morph into other people, or to BE one person but physically look like someone else i know. when i am pregnant i tend to have more vivid and more frequently scary dreams, including one with my long deceased mother as a zombie (had a hard time sleeping for a few days after THAT one).
if i am intensely absorbed in something, that will come out in my dreams. someone posted a few days ago about video game dreams. i am a gamer and after a particularly long gaming session i sometimes do have dreams about whatever i was playing. thats one way i know i need to step back because i am spending too much time gaming =) likewise if i have an important event happening the next day, i tend to have bouts of insomnia the night before and barely sleep, and when i do sleep, its fitful and punctuated by frequent dreams usually revolving around the event.
there is one dream ive had.... i cant tell you now what its about or what happened in it, but when ive had it, i absolutely know that i have had that exact dream before, multiple times. i usually remember it right after waking but it fades from my memory quickly. i always know ive had the dream before, but i can never remember it for long. its been a few years since i last had it, maybe next time i will write it down. this has happened maybe half a dozen times throughout my life, with the same dream.
i tend to think autistic dreams are probably the same as non-autistic dreams: widely varied, covering a lot of different topics and in different "styles". how we react to and perceive them may be different tho.