I run DA 7800. So far so good.
Ultegra will not make any noticeable difference compared to DA.....but DA is lighter.....thats the main benefit.
Ultegra will do you well.....I like the new ICE grey look too.
I chose DA over Ultegra because I got my frameset at a discounted price so I was able to spec up my bike to my budget.
The Cayo's aren't bad looking. The white trim on the £1699 jobbie is a bit bland....but it's well specced with SRAM Force and Fulcrum 3's. 10/10 review in Cycling plus too. Go for that if thats in your budget! You'll be well pleased.....although
Wiggle haven't any in stock........like most of their Focus range....you'll be waiting for another 6-7 weeks yet.