Hi TravisMT81! I took a very similar trip to the one you're describing last year, only in reverse. I flew MCO to SFO, and then LAX back to MCO. I found the most affordable airline was Airtran (since MCO is a focus city for them and their HQ is located here).

Their planes were quite clean (their whole fleet is only 3-4 years old). I found their seats to be comfortable for economy class. They don't have much in the way of in-flight entertainment, but they do have XM radio and they give out free headsets for it. As for time, it did take most of the day, but their flights did run on time (and even arrived a few minutes early about half the time) and the connections in ATL were easy to make since their gates are all in the same terminal. If you sleep easily on planes, a redeye will make the time pass very quickly. My LAX-ATL-MCO flights went quite quick as I fell asleep after takeoff and didn't wake up again until it was time to land.

And if you plan to make this trip often, it's not too difficult to earn free trip with them (2 R/Ts gets you a free upgrade to business, 4 R/Ts gets you a free O/W, 8 R/Ts gets you a free R/T). I hope this helps and good luck booking your flights. The City Beautiful here is worth the effort.