We have only cruised NCL twice. Last summer we did a Venice R/T on the Jade and were impressed enough to try NCL again. have also been on one Celebrity and two Windstars before kids, and one RCL with kids.
Since we have three kids we chose the two bedroom suite instead of adjoining cabins. You get some significant perks from the suites that make the price difference worth it in my opinion. The two bedroom suites are a very nice option for large families that give you a lot of room, as well as privacy when you want it.
Positives: