It's been years since we sailed Princess but found they did anytime dining better, loved the little details around food/hosting like milk & cookies, the movies under the stars with popcorn, the real ice cream and waffle station.
I prefer the cabin sizes and layouts on Royal. Royal especially on the bigger ships does entertainment well, we've always had really good service and since we travel with a group of varying ages and interests it meets our needs better. I could happily sail princess, celebrity or royal and look at itinerary. My husband and the rest of our family and friends need more bells and whistles onboard, want good service, and food options so they're happy with Royal.
We continue to select my time dining but always have reservations (early is too early, late is often too late and sometimes we want earlier and sometimes we want later) and adjust onboard if need be (don't usually have too much trouble). My time dining looks like a zoo without reservations otherwise it's fine. We've done the UDP on symphony, that was great but too much food- a 3 night speciality is a good number. Coastal Kitchen on Wonder had us completely spoiled- so if I was in a junior suite or above and could access coastal kitchen I'd opt out of specialty dining. Embarkation lunch - we avoid windjammer and crowds, depending on the ship there are options (park cafe, solarium bistro, el loco fresh) but you can also pay for a specialty restaurant lunch.