I REALLY wanted first seating too. Thought the second would not work at all. We booked early enough that we got the first seating, but you know what.....we rebooked and asked for second instead. The first was fine, but we really did have to leave the fun stuff to go get cleaned up for dinner. Later in the days, the pools were much less crowded, but we couldn't stay b/c of dinner. We wanted to watch us sail away from St. Thomas, but we had to go on in to get ready for dinner. The first was fun, and we enjoyed meals very much, but I think it will allow a lot more time to do other things with the second seating.
If you want first, go to the dining changes place immediately...be first in line and hope for the best. If you are travelling in the off season, hopefully there will be a place available.
(There are such good foods all around the decks that we never really ate because after lunch, dinner was right around the corner. If the kids eat a hot dog at 4 pm next time, they will likely still enjoy dinner and not get hungry waiting for 8:30)