Hey, you were the one asking about SWA - I gave you the info you asked about an additional airport ;)
The biggest complaints I have from my friends (all who travel frequently and all have sworn NEVER to fly SWA again) is that it's like an airborne bus. Besides feeling like cattle, they don't code share with other airlines. With Delta I know if they cancel a flight, they can put me on another airline. SWA, doesn't happen.
Then again, I've been flying Delta since I was a few months old, my grandfather was one of the first investors and my uncle a pilot. Plus if you live in ATL you can't walk w/o tripping over someone who works for them so I have a lot of friends who are past or current employees. I like to keep the $$$ in my own state
I've driven to Birmingham to pick up my sister at the airport and it wasn't a bad drive for me, IMO. and I was driving a lot further than from airport to airport. If you want to really fly SWA, you could rent a car. Having a car in ATL would be nice IMO, but I'm also a snob about riding MARTA