There is only 1 formal night. It is very similar to 7 day cruise formal nights. The Ecstacy and Fantasy are easier ships to navigate around on. I have been on both of those ships, and the Sensation, and had a great time. I have had great service on those ships also. There may be less food choices at the buffet. I can't think of a reason why it would be a bad vacation. Progresso is a good stop for the Mayan Ruins. I just returned from the Conquest and my wife said yesterday she would like to round out our summer on the Fantasy.