I know many like the thought of the tips just being added automatically to their accounts, however, I am old-fashioned, and like to tip on my own.
One of the first things I do when I board is go to the purser's desk to CANCEL the auto tip. It is not hard, you are not pressured into keeping it or anything like that. Very simple, tell them "no thank you"
I am very glad I did, as our room steward was NOT deserving of any sort of gratutity, but our waiter & assistant waiter were more than deserving - so they got the room steward's share.
I prefer the traditional seating, but was unable to get it this cruise. However, we were able to have almost the same thing with the personal choice dining. We arrived early the first evening (Michalangelo dining deck 5) and were able to request a table for 4 next to the window (I enjoy watching the water). Because we liked our location and the wait staff, we simply spoke with the head waiter and requested that that be OUR table & staff for the rest of the cruise. The only thing they requested is that we keep to the same basic time frame (early seating - 5:30 - 6pm arrival).
The disadvantage of the personal choice dining rooms (for first time cruisers) is the lack of some of the traditional touches such as the parade of baked alaska on the last night.
Don't forget, that you can request any special meal request you like - it just may take a couple days before they are able to serve it (I was traveling with a girl that had a craving for a special asian chicken dish)