I bought this book for my sister, who is a student living in NYC. She's lived there for about 4 months (with my other sister has lived there for 3.5 years) so she's definitely not a tourist, but neither is she a native New Yorker. We tried to use this book when I came up for a visit. I'm not sure why they list every Dunkin Donuts and Starbucks in each neighborhood. I'm pretty sure that locals already know and/or don't care where those places are. Seems like something tourists would want to know. I was surprised at places that were left out, including a few places to eat and shop, which I thought would be appealing to locals. Also, the maps assume the reader is intimately familiar with all of the streets in each neighborhood. NYC is a big city, so while one can be a local in one neighborhood, I'm sure even long-time New Yorkers don't know where every street in the city is. A grid on the map would have made things easier, or numbering each of the places of interest.
So while I hope this book is useful to sis, I don't think it's going to be the resource I thought it was. Thankfully, I also got her Off the Beaten (Subway) Track Off the Beaten (Subway) Track: New York City's Best Unusual Attractions, which I think would be much more interesting to locals than the NFT guide.