This is an awkward thing to make any generalization out of.
A common impression is that people with Asperger's are weird, eccenctric, odd, yet innocently happy with who and what they are/do in life. When you look past the oddities, you'll notice they're honest, good-minded peaceful people who just want to have fun and typically have the smarts to have fun in a smarter manner than most NT's do.
But like people who don't have Asperger's, some people just don't have the best of luck with other people; peers, parents, etc... and this leads to more issues. Issues like this can lead to depression or other mental illnesses, and at least in my observation, most of them come here because unlike in the previous paragraph, something went wrong in their life, so they can't be the "eccentric yet happy with it and joyful anyways", and thus come to here for help with their conditions (it's like a support group). Some are just lucky to blend in society well, and some aren't.
Those who aren't, wouldn't be the happy ones, and are the ones you're more likely to find here than elsewhere, in my opinion.
It just kind of goes down to how well it's worked for them, I think. For me it hasn't gone the best so I'm not always the happiest person.