In November 2003 we did the Mexican Riviera on the Vision of the Seas with 3 children aged 9, 7, & 5. In January 2005 we did the Mexican Riviera on Diamond Princess—a twin of Sapphire Princess—with another couple.
Vision of the Seas is a beautiful ship but was getting a bit worn on carpeting, etc. (The ship may have been reconditioned since November of 2003.) The Diamond Princess was newer and larger than the Vision, and has a little more formal decorating style than RCL. Although there are more people on the Diamond, I thought the Vision felt more crowded in its public areas.
The food was good on both ships and my opinion is split. I thought the buffet food was better on Vision—I especially enjoy their made-to-order omelets in the morning—and that the dining room food was better on Diamond. We also enjoyed having the various dining venues on Diamond. You will not go hungry on either ship.
The exercise area seemed to be about the same size, but was more crowded on Diamond. Since we had the children with us on Vision, we did not see any of the shows. We did enjoy the shows on Princess. The cabins are nicer on the Diamond.
Our children—although quite a bit younger than yours—loved the children’s program on Vision. We did not have children with us on Diamond, but the ship also had extensive children’s facilities.
I think Vision has a better itinerary than Sapphire. Although they both visit the same ports, Vision stops in Cabo first and Sapphire stops in Cabo last. Vision is in Cabo for a full day whereas Sapphire leaves about 2:00 making for a short day in Cabo. Sapphire leaves on Saturday and Vision on Sunday if this has any impact on your travel plans.
Finally, we have been on Princess 4 times and RCL 3 times. I think both lines do an excellent job and that you will have a wonderful cruise regardless of which one you choose. My own nod is to Princess, but that is more personal preference than anything else.
By the way, we enjoy this itinerary so much that we are leaving on the Sapphire Princess on January 14th.