Originally Posted by
BlatheringPenguin
The 319 is a totally different beast, as you'll see on seatguru. Really no good choices there in my opinion.
The exit windows on either HP or US A319s (about 10A or 10F) have nearly unlimited legroom with no seat in front (and you can use the space under 8A/8F), and are by far the best coach seats on the plane.
As for the 320 -v- 321/757, I wouldn't go out of my way to change planes (adding an hour +) for the extra legroom, unless I really needed the miles to top off my account. PHL-PHX flights are extremely tough to score upgrades on.