That's a tough all, coolmum. It depends on how much time you expect to spend in the suite, and how much space you'd like. If you are going to be spending a lot of time on shore or going to shows on the ship, it might not be worth it. But if you believe you and your family will feel cramped in a smaller cabin, it will be worth every penny.
Here are the floor plans for each:
for obstructed view family suite,
for the oceanview stateroom with balcony
I don't believe that the family suite comes with concierge service, although there's a lot more space and two TVs!
Sorry I couldn't be of more help with this one, as it comes down to personal preference.