This has been refuted from a living in base angle, and I'll also refute it from a commuting angle. I used to fly in the AA system and had to commute on either UA or DL to work. I greatly preferred taking DL through DTW, ATL, or MSP than UAL through ORD, IAD, or DEN. They just seemed to run consistently smoother, are more comfortable and passenger-friendly, and hotel options are better. These factors are even more important commuting to one of these bases every week.

I've never been based on the coasts but I think I'd prefer commuting to SEA over SFO and JFK over EWR.