There are small, but noticeable differences between the major airlines. All have friendly crews, and all have some unpleasant ones.
You mentioned AA with MRTC, that is definitely a big one. Also, I just flew United over the weekend and was impressed by E+ as well as the fact that they give you a full can of soda (and happily a second can if you trek back to the galley), have Channel 9 and free in-flight entertainment for those who do not find ATC engrossing.
It's not much, but it can make a trip a lot more enjoyable.