Here is some advice - Don't hang out at it all night or your dance floor will empty and people who don't know where you are will leave (I saw this at several weddings last year). I recommend hiring an owner who is also the photobooth operator who knows how to fix a printer or replace a faulty cable rather than someone who sends a kid making a low hourly wage who has no investment in how the night turns out. Check out these companies.
In addition, many photographers offer fun photo walls with props that accommodate larger number of people at the same time. I'm a fan of these.