I like younger kids. There's a certain simplicity and honesty to their view of life: they aren't as jaded and sour as they will be in 20-30 years.
But the constant need for attention is overwhelming after a few hours. You literally can't take more than a few minutes off without paying attention to them. And for 18 years...
What I do is borrow them from friends. Their parents are usually more than happy to get rid of them for the day and I take them to a park or to my weekend cabin (where there aren't expensive things to break).
However these kids are well disciplined. I have nothing to do with kids who can't behave or who have clueless parents.
_________________________
"If they can't picture me with a knife, forcing them to strip in an alley, I don't want any part of it. It's humiliating." - windsock