I know a number of people on here don't seem to like them but we have been flying them since 1990 (5 times so far.) Like every airline they aren't perfect but I love them.
We PREFER to go open jaw so SFO in, LA out.
The staff have always been great and because you are travelling mostly with Americans there are less "aliens" arriving with you when you get to LAX.
They mainly serve American sodas and drinks and the food has always been good.
They have always been reliable. The only time we ever had a "problem" was a medical emergency on the connection to MCO and they did everything they could to get us going soon.
Their fleet is older but well maintained. The Pilots have all seemed excellent (as opposed to BA where we bounced on landing.)
They don't have in seat entertainment which is a negative to a some people but having now experienced it on 3 different airlines now I'm not too fussed.
My FAVOURITE part about them is Economy Plus. This is their version of premium economy but is actually affordable because the benefit is the main thing we want - LEG ROOM. The seats are the same but they are further apart allowing for more leg room. You can buy access for around US$250 a year and get you and another person travelling with you into Economy Plus for all flights with it you travel on during that year.
That's the way I feel. I hope it helps...but as I say there are others on here who didn't have a good experience.
I have now flown Finnair, Qantas, American, Hawaiian, Air France, KLM, JAL, United and Alitalia. Oh and US Airways - Never Ever Ever again.
I think this is a pretty good range of experiences to compare to.
Finnair is the best I have ever flown but you pay for it.