We use Delta and Southwest. I haven't been too happy with Delta lately because they always seem to change your flight times after you have already booked. Our April flight originally was for 220pm, it was moved to 327pm then again to 347pm. I called and was able to switch to the 710am flight with no charge because they changed the flight time over an hour from my original time.
Our February flight was moved up an hour as well. Also it seems like Delta is always late leaving Orlando, I don't think I've ever departed when I was supposed to with Delta. I do prefer Southwest because I haven't had those issues with them, but I usually just suck it up and go with the cheaper flight.