For those that have flown on carriers with newer-generation A320-family aircraft, like Virgin America or a number of foreign carriers, you've probably noticed that bags which normally didn't fit handles- or wheels-in on United's A319/A320 aircraft would on the newer Airbus. The newer doors have a greater radius that effectively deepen the bin, and these retrofit doors appear to be similar, including the handle.

My carry-on bag would typically need to stow long side in on UA's A319/320, but would easily go handles- or wheels-in on VX. One section of bins that would previously store 2 bags long-ways can now roughly fit 3 bags short-ways...voila, a 50% increase in space!