Well, to put it into perspective for you....
I'm a PHL resident and was a long time US flyer. I defected to AA a few years ago and love it. Their service out of PHL requires connecting at DFW and ORD mostly, but that doesn't really bother me. I'm only 200K away from lifetime gold too.
My observations:
1.) US upgrade policy - while generous by giving "free unlimited" upgrades to all 4 tiers - often leaves the lower tiers with very little chance.
2.) The boarding process is annoying without the Priority AAccess line. I love being able to come out of the club, or take my time getting to the gate, and saunter onto the red carpet without fighting the hoards of gate lurkers.
3.) First class service is above and beyond USAirways. The meals. The glassware (US still serves drinks in plastic cups).
4.) Wifi - US has finally put WiFi into their whole A321 fleet, which is nice. AA is moving along well with their MD80 fleet and I think 737's too.
5.) In seat power - US turned all their in-seat power outlets off a few years ago when they removed their in flight entertainment systems to save weight/conserve fuel. AA has in seat power at all F seats in their mainline fleet, and at select coach seats that I can always select in advance. AA also has IFE on flights of varying lengths. You will be without any audio/video entertainment or in-seat power on every single domestic USAirways flight you take, including caribbean trips.
6.) Award redemption - US makes it very hard (and expensive) to redeem for travel on their own metal. But the Star Alliance is a great network, especially with CO in it now. Generally, I find *A stronger than OW in terms of options.
7.) Status match - US won't match your status, but they will let you pay for *ANY* level of elite, and also pay for a status match to some levels.
8.) I guess with the pending FA and Mechanic strike, AA customers have been feeling some negative vibes from the frontline staff. But be advised that there are more than a few reports here about very lazy and downright nasty front line folks at US due to the ongoing labor integration issues and an uncaring management. Don't let the name fool you - the company is still two very distinct airlines - USAirways and America West.