I took my first flight ever on US metal 2 weeks ago. ORD-PHL on an A321 in F. The plane was disgusting. Torn seats and carpet, missing and hanging trim pieces on the walls, peeling paint (or whatever that top coating is) in the overhead bins, and third world lavs. I found the seat pitch to be less than AA first and the seats were very uncomfortable compared to the AA 737 F seats. The best word to describe it is "grim". I can't imagine how it was in back, especially without MCE available. Unless and until the legacy US planes are brought up to AA standards (which are not that high to begin with), I am done with US metal.
Cabin crew was okay. Not any different from AA F crews.
As a "hard core" AA flyer - I've found the crews on the few US flights I 've taken to be very friendly. They always greet everyone, offer PDBs, etc. But I've also found some of them to very slow with the service, especially full meals. They obvioiusly aren't used to it.
But I can't say I've been on ANY US Aircraft that I would call nice. I was on an A321 last night which had LED lights (so I'm assuming is somewhat new), but the seats are old and janky, and I don't care for the small galley and lack of closet up front. It just looks trashy how they have the plane configured.
US air cabins are all absolute trash, and you can tell they have/had no interest in investing in their hard product to make it comfortable or offer any ammenities while on board.
That being said, I'll take an AA plane any day over US AIR, despite how friendly the US AIr crews might be.