I've flown USAir quite a bit and had no trouble with them. In fact, they were my preferred airline for quite a while but mainly because when my sister lived in Ohio, they had the most flights at the times that I wanted to fly out there.
That's not to say that they were perfect. I have had some problems with them. The first, would be weather related more than anything, so it didn't stop me from flying with them. It was Christmas Eve a few years back when half the country was dealing with ice storms and extreme cold. We were delayed and delayed and delayed, but eventually arrived in Ohio.
Another time however...our flight from Boston had a stop in Pittsburgh and then on to Dayton. No changing planes - just a stop. We were delayed leaving Boston, but not too bad. Arrived in Pitt and the other passengers got off. Those of us flying onto Dayton stayed on. We sat there for at least 20 minutes when we could hear the flight crew talking. Come to find out, they sent another plane from Pitt to Dayton in our place and decided that our plane wasn't going to Dayton that night. There were at least a dozen passengers. And at first, they weren't going to put us up in a hotel...but we fought for it and eventually won out. They also messed up my rebooking, but I got that fixed when I checked in the next morning...but my luggage ended up on the later flight.
Probably more nfo than you wanted. But I would still fly them.