Do you know what visa you're coming under? I think h1b dependents can't work but intra company transfer can. Nearly all visas allow dependants but some (eg student) may require evidence that the dependants can be supported.
Life here is expensive. We pay $5500 per month rent. You can find a 3 bed for less though but not in manhattan or pay less for a 2 bed. We spend about 50% more on food than London. Health insurance costs us $800 per month (employer contributes 1500).
You don't have to pay for public schools but you will pay increased rent to live in the right school zone (very important!). Private schools in manhattan are super expensive - around $40,000 pa. catholic/Jewish schools tend to be cheaper as do those not in manhattan.
You have to check out the health insurance very very carefully. Don't just look at your premium, also look at the copays, deductibles, limits, exclusions etc.
Nice places to live depends on what you want! Do you want the manhattan lifestyle? The outer boroughs (eg Brooklyn or queens)? Proper suburbia eg in westchester, Connecticut or nj? Where will your dh need to commute to?
DH has the possibility of transferring to NY, it is not something we have even considered before so has come completely out of the blue and I have so many thoughts at the moment, so starting the research here! Does anyone have experience of this? I don't know how the visas work, will I be able to work if we come on his visa, is that even possible? I understand it may be hard to find work, but need to know if I can even apply for jobs (and enter on his visa more importantly) How much do you need for a family to live comfortably? What should we expect from his employer with regards to health insurance etc? Do you have to pay for good schools? Where are nice places to live? It sounds so exciting, but how is the reality and the lifestyle with small children? TIA for any advice