I'll agree that Sleepers are quite civilized and are a pleasant way to travel, though it would be nicer if the trains were smoother and faster.
But I vehemently disagree with regular coach seating. Yes, you have more leg room and can get up and move about. But given a flight from Philly is less than 3 hours, and you're talking well over 20 to Florida, at least the flight is over quickly.
The sheer number of bodily odors and sounds that you are subject to, the constant sleep interruption when you stop in the middle of the night, the cranky toddler, the inconsiderate person not using headphones with his laptop, the rush to make cell phone calls when you hit a coverage area (no matter the hour)....should I go on? Ok...the barely edible food in the dining car....the microwave vending machine quality food from the club car....then if you are so lucky you get the poorly latching restroom that hits its capacity mid-trip.
Then there's the homeless people that are welcomed with open arms at train stations and the barely decipherable train boarding announcements (though this may only be a problem in DC's Union Station). And the occasional ten hour delay in the middle of nowhere....at least in an airport the bathrooms don't run out of flushing fluid mid-trip.
So yes, travelling in a sleeper is civilized, but you have to be pretty scared of flying to take the long distance trains, since the train is usually a bit more expensive than flying from big cities.