dms
911
Blue
If I had to pick only ONE, and if I had no other Reverso, I would go for the blue for 2 reasons: great blue dial, and a "second" watch when you flip the dial.
This is why my first Reverso was a Grande GMT (over a Grande Date): two different dials, so different that, from time to time, my preference varies from one to the other…
But I had to add the Red for its coolness