I am a library student and have been using the Jersey City libraries for the past year, as well as another library system (where I work). I love the Heights and Pavonia branches, as well as the Main branch - which I visited for the first time today. Employees are welcoming and the environment is satisfyingly quiet, but active. I love using my neighborhood libraries, it makes me feel like a bigger part of the community. The sharing, free, democratic nature of libraries is very appealing - so use your library!!!
For those who have had less than perfect experiences, speak up to your library staff!

If you are not happy with operating hours, make suggestions. If the collection seems dated, make suggestions. Libraries are very open to new ideas, and have supported communities for a very long time. It is the community that keep the library dynamic!