Personal preference for early seating for DH and me.
a. We typically eat around 6 pm, so pushing that back to 8:15 as we tried on one cruise meant eating lots of snacks late in the day so we aren't hangry in the last 2 hours before dinner. My husband has a pretty good metabolism, but the timing wasn't good for us.
b. One time we were with several other adult tables for late dining on a cruise ('met' via a social media group)-- it took forever to eat. We could be one of the first groups in the dining room, but partly due to the size of our group, we never made it out of the MDR before 10:30 and missed a lot of shows that started at 10pm.
c. We'd rather eat early, THEN relax for a bit, THEN see the main show, and then if we want to treat ourselves to a nightcap or extra dessert, we get that before retiring. When we ate late, it was like, ugh, that's finally over, let's flop into bed and call it a night.
I realize this is mostly just our experience, but that's what you were asking for, correct?