I can offer a lot of insight in this thread, since I happen to be a nomad who lived in every borough and lived or stayed at Nassau and Suffolk county in Long Island (Hempstead, Freeport, massapequa, Gordon heights, medford, stony brook, bay shore to name a few). 
For starters Long Island is extremely segregated. Then again most of NY is except for queens (Astoria Specificially). Long Island was built by white flight from the city. That's why the parkways have low bridges. There were designed that way by Robert Moses to keep the urban buses out. Also there are hoods throughout. Between the Indian reservations in Mastic, to bellport, Hempstead, and Wyandanch you definitely have nikkas who be about that life. 
There are a lot of things I hate about Long Island. Lots of close minded people both black and white. I find a lot of brothers with that slave mentality and whites who only know about the world via Fox News. It lacks diversity too. I feel like every shop is Starbucks, target, sushi place, nail/spa/bagel/pizza shop and karate place.
The plus side are the incredible beaches and such. World class if you ask me. I feel like if you starting a family it's a good place to be. Between the parks, beaches, marinas, vineyards, amusement parks, ferrys and such there's alot to do with kids.  For younger people I would stay away and just be in the city.