I've flown USAir exactly once, about 6 years ago, so I can't comment on their seats. I just wanted to make a general observation on seat pitch.
Seat Pitch is the distance between the rows of seats and is measured from the back of one seat to the back of the seat behind, the measurements being taken from the same position on each seat. So far, so good, so measures on websites like seatguru are very helpful. However ... the thing that seat pitch charts tend not to tell you is how thick the seat cushions are. If the seating is older and the cushions are thicker, the usable distance from the front of one seat to the back of the one in front of it will be a bit less. The newer the seats, the thinner the seatbacks tend to be. Of course, squishiness also counts, but the foam only squishes so far.