My experience has actually been the opposite. I usually fly WN or DL out of BWI simply because they are usually the cheapest option, but a few months ago I flew on AirTran. I got an inexpensive gate-upgrade to business class on the way down, but on the way back, I was in coach, and I noticed how much less leg room there seemed to be than on the other two airlines.

It had never occurred to me that different airlines have differing amounts of space between seats, though I guess it makes sense. I hadn't flown anything but WN or DL in over five years, so I guess I got used to it.

Could it have just been the plane I was on?

Though I rarely have status on any airline, I still prefer to fly an airline that has first or business class, so I can get a paid upgrade or use miles or points to get the upgrade. I wish WN would integrate that into their model instead of doing away with it completely.