I was able to attend all three, and brunch was by far the best meal of the entire cruise!
We had Erika for our server, and she was the best server we've ever had, anywhere. Even better than Ron at Jiko at the AKL, and that says a LOT!
The tea was fun and good, but certainly not "world class". It almost seemed like an afterthought.
As far as dress, at brunch dressy casual is fine. I want to think I wore a resort wear type pant suit and DH wore chinos and a polo type shirt.
Dinner is much dressier, I think they suggest a jacket for men and dressier pant suit or dress for women, although it's not uncommon to see formal attire there as well.
Tea is also dressy casual, but slightly more on the casual side. I had tea with another Dis Board'er, I wore a sundress and she wore a skirt and blouse, and we both felt just right.
Enjoy!
Anne