To be fair, this has nothing to do with US Airways… from what I understand, before the merger, F upgrades were fairly common on US.
Exactly. I've been most status levels with both US and AA, and it was definitely easier to get upgrades in the US system. Plus the US A319 had 12 F seats.
As a moderator for the US forum here on FT, it was quite common to hear of US Silver (the lowest level, similar to AA Gold today) getting upgraded quite a bit. CP (Chairman's Preferred) was nearly guaranteed upgrades. The US versions of SWUs were fairly easy to use and I never had problems using them.