I have flown both and there are advantages for each of them. SW allows 2 free checked bags and they don't charge a fee if you should need to change your flight. They also seem to have more non stop flights. JB allows you to prebook your seats, have unlimited snacks (and better if that matters!), seats seem to be a little roomier but the biggest advantage for me is the satellite tv. If the price was the same I would choose JB but SW seems to always be a bit cheaper.