Yes, would really enjoy some detailed input about the DO balcony cabin on the Sun Princess. I have spoken with Princess Cruise Line reps on a couple of occasions about it and they are uncertain what makes this cabin "Premium", other than the size of the balcony. Seems to me it's quite pricey if that's the only difference between that and a regular balcony...
I did notice that on cruisedeckplans.com, if you click on the Sun Princess DO balcony cabin and look at the Features tab, down at the bottom it reads "Category DO balconies include Signature Benefits." This website is not related to the official Princess Cruise Line website, so I have no idea how accurate the information is.
I, too, am very curious to hear from passengers who actually stayed in the DO category cabin.