I guess a lot of that would depend on the severity of the autism.
For example, a person with Down's syndrome and a person with moderate-functioning autism might have the same IQ, but the person with Down's syndrome will have an easier time finding a job.
This is because there is still a misconception that Down's Syndrome= placid, obedient, childlike and Autism= defiant, violent, un-friendly.
Now...a person with high-functioning autism/Asperger's might also have a slightly harder time finding a grunt job than a person with Down's Syndrome, because the employer expects the person with HFA/AS to interview like anyone else. However, they won't have as hard of a time as someone with a more severe form of autism, due to the fact that an employer might not be able to tell that there is anything wrong with them, and hire them over the person who obviously has something wrong with them (the person with Down's).
When it comes to getting a job that ISN'T a grunt/*"smile" job, then a person with HFA/AS (assuming they had decent qualifications) would win, hands down.
*A "smile" job being, any low-skill job that emphasizes friendliness without any substance (exe. A Wal-Mart greeter)
As far as what's "easier" for daily living, it depends on how you define "easy".
It can amount to two questions:
1. What are your ambitions in life?
2. Do you want people to treat you differently, because of your disability?
If the answers are "Not much." and "Yes", then having Down's Syndrome is easier.