Incase anyone is considering going - definitely go.
We went for a week with Katz last week and it was amazing. Everything about it was fab. It was a busy hectic week away and we only got to do half of what we had planned - we will have to return some time to do the rest.
It is definitely child friendly (although I wouldn't want to have a baby in a pushchair on the subway). DD (7y) and Katz's DDs (6y and 3y) had a great time.
We stayed in a lovely town house right on the bay. The deck looked directly onto Jamaica Bay, with the bird sanctuary opposite, and with fantastic views of the Manhattan skyline. The sunset was stunning to watch. Manhattan was 45 minutes away by subway, which was a really easy journey and passed really quickly.
And the people were so friendly, probably the friendliest city I have been too. Not once did we get on the subway without having a seat. If it was busy almost immediately someone would offer their seats for us and the children, not wanting to take no for an answer. If someon saw us with a map book or guide out they asked if they could help. And we met a wonderful lady on the subway who helped us find the right track in a very busy station - by going out of her way and taking us there! And a number of times people suggested a better cafe or restaurant to us if the one we were looking at looked busy or they saw us trying to decide.
Thanks to all those who recommended places for us to visit whilst there.
Overall a fantastic place to visit - and it really is just like it is in the movies