On Princess's ships that offer "Personal Choice Dining" (which has expanded to seven of the ten vessels), I'll take "traditional seating" over "anytime seating" (Princess's term for the new option), any time. Here's why.
>> 1. The service is much better because your waitstaff get to know your preferences on the first night or two and thus anticipate your requests thereafter.
>> 2. You have a chance to get to know your tablemates over the duration of the cruise rather than meeting new tablemates on a precursory basis each night.
>> 3. The two seatings of the "traditional seating" arrangement are timed to align with the shows and other evening entertainment. Thus, you probably will end up eating more or less at those times anyway if you plan to attend the shows and other events.
>> 4. There's a lot less traffic going by your table while you are eating in the "traditional seating" arrangement because everybody in your seating is on the same schedule. In the "anytime seating" arrangement, there's a steady stream of passengers entering and leaving the dining room throughout your meal.