I can only speak from our families experiences on the Zaandam and Maasdam. The boys (were bored to tears at the kids program. We went on a non holiday time in November and in May (with Grandparents who are only HAL cruisers).
The good: the cabins are large and the staff were all great to the kids (except the kids program staff - who were surly and bored). There were very few kids on board, may a dozen or so. No problem getting loungers by the pool (all the people were playing bingo - no kidding).
The bad: the food (think banquet hall food). The kids program. Not that I want to be flamed for this, but the number of people with wheelchairs, walkers, oxygen tanks was pretty shocking. Horrible customer service on the Zaandam (no A/C for the whole week and they would do nothing). Maasdam was better for food.
My boys have also been on NCL (Spirit and the Gem) and said (unprompted I might add) that "I liked the cruise on HAL but I liked the one on the Spirit 100x better" this was a day or so before we left on the Gem. I know they liked the Gem even more. I have very easy to please boys BTW.
I personally think there are better choices for those with younger children for a non-school break week.
That being said, my in laws love HAL and have hundreds of sea days with them and have booked an upcoming 35 day from Vancouver on the Statendam, they have done Alaska, Mexico, Hawaii, Caribbean etc as well (so lots of 7days). It is right up their alley, they are both about 79.