As a Song/Delta/JetBlue/best deal fan, I can go one better than what Delta's telling you. The Song jets will be reassigned to long-distance flights of 1,750 miles or more. These are the flights that will have the tv in the seatbacks. It's been a while since I've been on an actual Delta flight but to the best of my recollection they do NOT have tv screens - just the displays that come down from overhead in the aisle.
As for food, passengers are welcome to bring their own food on any airline's planes (I'm not even going to go into my diatribe about why we don't feel we can survive without food for three hours

).
And regarding cheaper, well, I'm perfectly willing to fly multiple airlines to get the best deal; I've been able to match Song with Jetblue, and the reverse, but by planning ahead I've never found one of them offering 'better' prices than the other.
Another bit of confusing travel terminology that needs to be better understood by customers so they know exactly what they're getting:
A "direct" flight means one plane that flies from point A to point B, with a stop at point C in between (and possibly even point D). The plane takes off, lands somewhere, some people get off, others board, the plane takes off again and probably flies to your destination.
A "non-stop" flight is probably what people mean when they say 'direct'. A non-stop flight doesn't stop between the point of originaition and the destination.
More terminology

The red-eye generally refers to a late-night departure where the plane (and its passengers) fly overnight over a several-hour period. Someone flying out from the West Coast to Floridaon a 10 PM departure is on the red-eye; a passenger departing New York for Florida at the same time is on a plain-old late-night flight.