Have been on both ships. Taking into account the ages of your children and having travelled with my kids (at various times and at various ages and with another family and their kids)several times between the various cruise lines too, I would say that the older child would prefer the "awe" factor of the bigger ship. The ice skating, the rock climbing, the club for teens 12 - 14,and your other child at 5 will not really see difference between Victory and Adventure of the Seas. Don't know whether CArnival has Any time dining yet but RCCL has and that works pretty good when you have a younger child with you. Eat when you want type of thing in the diningroom. You can reserve different times different days too or just show up with Anytime on RCCL. Our kids liked the Promenade - a mall like concept and the parades that occur there at least twice during the cruise. The teen will like the Johnny Rockets $4.50. As a first time cruiser, you really have nothing to compare but I can tell you that either ship you choose, will be very busy. We did Xmas cruise on Princess Emerald this past xmas and there was no lack of friends to make. Lots for parents to do on either ship. For your first cruise, you are choosing well with the size of the ships. Adventure 138,000 and Victory 101,000 I seem to remember. A lot of people will say bigger, more people, I say bigger is beautiful. I can't wait to cruise again and we are watching for deals (ha ha) on the Oasis. Hope this helps with your deliberations.