I don't have any counter space that does not have overhead cabinets so there really isn't place to sit on them. But, my kids always sit on the table and I usually remind them to get off...
I could be I do, I'm not even sure!
My kids sit on the counter all the time. Usually only when it's totally clear. They like the view from the window! When I grew up it was scandalous to sit on the counter. Don't ask me why.