United Airlines has "Economy Plus" seating, which is the same thing as Delta's Economy Comfort, with a few inches of extra legroom.
And then there's USAir, which offers "Choice Seats." The airline's website describes these seats as follows:
Be among the first to board (with Zone 2) and among the first to leave when you land. ChoiceSeats are mostly window and aisle seats toward the front of Coach and may include exit row seats. You'll find the same leg room as other seats, but you'll be closer to the front of the plane.So on USAir you pay a big premium for a Choice Seat with the only reward being getting on and off early. That's a pretty weak reward. Extra legroom and free whiskey I'll pay for, but I'm not paying a big premium just to get off the plane two minutes before everyone else.