I have done this same routing the past 2 months both in FC/767 transcon.
First trip was on UA (MIA-IAD-SFO) Of course the E70 was nothing to write about but the 767 2 class from IAD-SFO was the typical crap seats, overhead movie and standard dinner with slice of cheesecake then done.
Now AA (MIA-LAX-SFO) I booked the 763 that is sold as 2 class but has the flatbeds. First impression the seats are not a nice as UA new Intl 3 class 767 but still are quite good. Now the service!!! I was BLOWN away^ I felt like I was on a Intl flight. The salad in a nice glass bowl, wonderful chicken appitizer, yummy bread and steak (a bit bland but ok) Then came the great sundae cart, hot fudge, caramel, strawberries, nuts, oh my
Then after all that chocolates and then hot cookies before we landed.
I am so amazed by the service level on AA I just wanted to share and kudos to AA.