I voted for Hamburgers, since they're neater, and people can put on what they like for toppings -- with Sloppy Joes, you're committed to the tomatoe'y flavour.

But -- if you wanted to go for a bit of a twist, do 1/2 of each -- of, put the sloppy joe stuff on the hot dogs instead of on its own, and make them into chili dogs or something