I think they're all pretty sweet. For some reason I'm drawn to the first one though. I think it's because the subject in the foreground is so centered, it seems odd, but works well because of the line of swings on the left.
Good stuff! I'd like to see the chain to one side of the frame and the background be the trees (no swing set showing) to make me wonder "where is that chain coming from/going", but that's probably just me.