I will share my observations based on our recent summer day visit.
Lot of buildings and facilities are modern and newer and the immediate neighborhood (2-3 blocks surrounding the campus) seem safe. As @MYOS1634 said, the city of Newark problems are much bigger and won’t get addressed anytime soon, but i agree with the eco-system being built in and around the campus makes it a very compelling and financially viable option for both in-state and OOS students who are interested especially in the STEM and Architecture programs.
The University Heights section of Newark is for all practical purposes a college town in an urban setting. Being well connected by rail, bus and automobiles makes it easy for commuters but NJIT has invested a lot in housing with the opening of the new Maple Hall residence section and close to 50% of freshman staying on campus.