I used to use Southwest a lot until I started discovering the joys of having status on an old-school carrier. If you fly less than 25,000 miles a year then Southwest is great, but if you fly more (and especially if you get up to 50 or 100K miles) then the perks of United (or similar) become irresistible.
I don't have status with anyone, but I'm usually broke. My impression is that having status with a carrier gets you perks, it doesn't so much make the experience as cheap as Southwest (and if you're strictly flying domestically, you're talking a 6-hour flight, max. That's really not that bad).
