Bibliographic management tools are a bit more robust than standard citation generators. They generally allow users to store multiple file types and collaborate and share libraries with other researchers. Users are, in effect, creating their own portable, electronic libraries that can house years of accumulated research that can be accessed, organized, and referenced with ease.
Citation generators are usually used when writers need one or two citations quickly and will probably not reuse the same material. However, some generators are beginning to offer memberships that allow users to save and reuse bibliographies.
There are a multitude of bibliographic management tools available. If you don't like what you see here, a quick search will reveal others. Most bibliographic managers allow users to import/export from one to the other, so there's no harm in trying multiple tools to see which one you like. If you plan to continue your research, this is the time to find a bibliographic manager you like using.