Boarding early has at least two advantages:
1. Overhead bin space is available. This is critically important to frequent flyers like me who may not check bags very often.
2. A pre-departure drink in first class. This is nice, but I can get the same thing in the CRC, if I have time.
So, I vote for pre-boarding First Class and Medallions. If Delta starts to be too much like Southwest, I might as well fly Southwest!
Bruce