I would respectfully disagree with those who say the Vibe is not necessary on the Prima. As others have noted it is not crowded, never a search for a comfortable lounge and an attentive bar staff. The buffet is just outside the door to the Vibe so super easy to pick up lunch and enjoy outside at one of the tables. On our cruise last February there were many unhappy people because of the lounge situation by the pools.
We have already booked Vibe for Viva in February 24.