I've flown every airline on that list except northwest. I've never had a major problem with any of the airlines. I've had a few delays, but nothing bad, etc. Never had any luggage lost, although I have had it come in early
Becasue of this, I evaluate flights by the amount of legroom. However, this even varies heavily among different flights on the same airline. Both the best and worst amounts of legroom I've had were on american flights.
So basically, whichever gets me there the cheapest, which changes all the time.