As SLF I'll throw this in- I've flown just about every major carrier in the US at some point. Not wanting to kick anybody when they are down, I'll just say- I've never found USAir/USAirways service to be all that impressive. I don't care what one's "cost structure" is- your livlihood depends on beating, i.e. "outservicing", the other airline. Certainly the other factors play in- but bottom line- USAirways is never my first or second choice- all things being equal. Please bear in mind, in the past I qualified for "Preferred" status in their FF program- so my opinion is not based on one data point- nor do I infer there are not any good or excellent people working there- there are, I've met them- but again, in general- my opinion stands as above.
All that said and not wanting to sound disingenuous- Good Luck to USAirways- it won't be good for anyone if they go away...