Congratulations on booking your cruise! You'll find a lot of things have changed in the world of cruising since 1990.
Early or late seating: what time do you usually eat dinner? Advantages of early seat include finishing with tons of time to spare to enjoy the ship for several hours after dinner. And if you usually eat dinner any time around 6 or 6:30pm, this is your seating.
Advantages to late seating include time to shower, change, relax, have a drink or do some dancing before dinner. No rushing home from shore. Being able to have an afternoon snack or "tea" and be hungry for dinner. Disadvantages include getting out of dinner at 10:30pm and not having a lot of time to hit the lounges, casino, etc.
I'm sure other folks will add advantages and disadvantagese to both seatings as well.
Our last cruise we did early seating..it was great. Had time to see the 8pm shows and turn in early! The kids (teens) went to all the late night activities...of course they slept in and did not attend breakfast with us in the main dining room the next morning. This month we are going on a cruise and booked early dining again. HOWEVER, this cruise I have come to realize is in getting into ports earlier and leaving a lot later than the other cruise we were on it was opposite. So we are actually having less time in ports. So, you may want to check out your own port times before making your decision.
We loved the late seating. All of the shows are typically designed for each seating to be able to catch them. A few nights, we did a show before dinner, ate, then joined up with the nightly activities on deck.
We also didn't feel rushed at all with getting back on board from your stop. Most of our stops had us leaving at 5:00-5:30, so it was nice to come back and relax before showering and dressing for dinner.
I have 2 cents to put in, we did the early seating on my first cruise and it did seem to be a lot of rushing so we could get to the dinner on time, so we are trying the late seating this time and plus this time we have children with us so that will be interesting to see how that works out. At least they have two sets of shows so I don't think you will miss a show or anything.
I like late, fiance likes early, so we trade off every cruise. There are advantages and disadvantages to both.
Keep in mind that [in general] there are fewer kids at the late seating (BIG perk, IMO), and the dining experience is more relaxed, since the servers don't have to get you on your way to get ready for the next seating. The fiance hates the late seating because the full belly makes him sleepy and ready for bed, so the rest of the evening is "wasted."