One, combatant commanders are in many ways bigger wheels than service chiefs. We'll see how those roll.
I've met them both. They are both hugely capable, but come at you from very different directions--for those of you who've been around a bit, their contrast is the same as LtGen Bedard and Gen Pace. For A4s, I would say that Mattis is Patton and Amos is Eisenhower. Both types of leadership have their place, and I think the SecDef is exactly right in his decision-making if this plays out the way some are speculating.
I've met other Flag Officers, and some of them make one think,"How did that guy get put in charge?" Neither one of these guys falls in that category.
As for those who have their pet theories about DADT or being in the pocket of the aerospace industry and such, I just don't buy any of it.
I, for one, think that some of the "outside the box," (to use a huge cliche) thinking, that we as aviators value, will be of great use during a time of huge change. Every other CMC has been a grunt. Maybe someone else can bring something different to the table.