I lived in the Belmont section of the Bronx for 4 years. There are definitely parts of the Bronx to avoid, though Throggs Neck and Riverdale are pretty nice.
But yeah, Manhattan is nice, it's just pretty expensive. Roommates are definitely a necessity unless you're bringing in some good money. And cars are definitely a huge hassle. They're pretty useless for inter-NYC travel, but if you're going to be leaving the city a lot, you'll need one. And parking is so expensive.
I don't know much about the other boroughs, to be honest, though I know there are some nice sections of Brooklyn and Queens. Some parts of Queens are almost suburban in nature. I know they both have some pretty bad neighborhoods too, and I honestly can't give you to much advice on which neighborhoods are better. I know Williamsburg in Brooklyn is famous for its hipsters though. You can infer what you'd like about that though haha.
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How should I put it? Life is like video footage.
Hard to edit. Directors, they never understood it.