This variety, the "Moon Jelly" is very popular here on the Emerald Coast.... They do pack quite a sting, yes it has happened to me, but nothing like the Man O War sting, according to the locals, of which, by the way, I'm dying to get a photo of.
An old photo of our very own "Hurricane Nate" wave, it's a treat to get the large ones on our coast line, if your a surfer, so I'm told.