Funjet charter flight

anyone fly on a funjet charter flight recently, say to Mexico? We will be soon doing so…on a Frontier A-320. Have never flown on a charter flt before so wish to know how this will differ from say a regularly scheduled Frontier flight. We have already learned that we may NOT select our seats till the morning of the flight. If someone has flown a funjet charter out of KMCI that would be nice to hear about as well.