I spent a whole year over on the Delta side this year, and I have to say, the grass is certainly greener on Delta if you're flying up front, but in Economy, JetBlue ever so slightly still edges them out. I had a decent time, but that's only because Delta recognized me as an Gold Medallion. I'd imagine that if you had no status at Delta, JetBlue would win hands down.
As far as the IFE being superior to JetBlue, that is changing. 28 A320s and all of the A321neos (3 in service right now) have the same system that Delta has.