We (family group of 8 / 3 rooms) choose this cruise for the Alaska outings and wanted to try the large ship with great looking laser tag and race track. You cannot book those 2 in advance. As a result, when you get on the ship, you need to book for your entire week and availability is very limited. Do not plan on that for entertainment. The slide my teens hoped to enjoy was closed the entire cruise. On the race track, you cannot bump and speeds are very restricted, passing is difficult so the person first in line will always be first at the end.
There are 4,000 people trying to eat in the Market Cafe which probably has seating for 1,000. It's a crowded mess and trying to sit with family is impossible (breakfast and lunch - horrible). Food is good, especially the Indian section. They must assume all cruising will pay for the additional restaurants. We did not, and when we saw some of those places they seemed available - for an additional fee.
Very little entertainment options so bring books and games. There is ~1 or 2 show options daily and again, if you did not book before you came on board, you will likely not be seeing a show. The comedians we did see where great. Jersey Boys also was terrific - I booked that pre-cruise.
We booked a spa balcony and are charged for the spa access, but teens are not allowed in. The spa though is beautiful with spectacular chairs that provide great views.