I don't have any problem with Manchester Airport other than their toilets. When dealing with schlepping around with luggage, jet lag, getting up early to catch a 5 AM train to the airport, etc., I really don't like to have to squat over the bowl rather than sit because there's piss all over the seat. I remember the very first time I arrived there, when I went to the toilet, asking myself "What kind of impression does this make for international visitors?"
I've never eaten in the Burger King there, so couldn't comment.