We just returned from an 8 night on Radiance and had a wonderful time. The staff are great, very friendly, patient, knowledgable. Our two teens came too, had a great time with other kids. We went over Christmas so knew it would be busy but you never felt overwhelmed by people (except at the end - disembarking - and that seems the same on all ships).
The food was fine, not great but plentiful, hot and reasonably varied. You can always ask for two entrees if you can't decide! (Like on lobster night along with prime rib or just order two lobsters as I did.)
The kids like pop cards, the adults don't bother.
We had an oceanview stateroom, it was very clean, everything worked well and the wonderful attendant coped with teens who like to sleep late (and order a lot of room service).
Radiance is going in for a total overhaul in a month or so but we did not feel things were worn or tired. They do keep refurbishing I guess due to sheer volume of people.
There are quiet spots you can find to sit, even on sea days if you want to get away from the pool congestion.
I know you will have a wonderful voyage.