Which is best? That completely depends on your needs and preferences. They are generally the same, but with different nuances and interfaces.
A comparison of citation management tools is available on WIkipedia, but there is no guarantee it is up-to-date. Otherwise, view tutorials or test managers to see which you like best.
These managers are free to use.
You will have to purchase access to EndNote or Papers yourself if you wish to use them. The Regent Library now subscribes to RefWorks Premier!
Citation management tools are useful for keeping track of and organizing the various materials (articles, books, etc.) you are considering using for a paper or project. They also help you quickly create citations for your resources in the style that you need (APA, MLA, Turabian, etc.).
Learning a citation management tool can be an investment, but usually, it is one that pays off. These tools are best for graduate students or anyone who is conducting research projects that involve a large number of resources for reference.
Always check that a manager is using the most current edition of your style.
Citations generated by managers are not always correct. Double check them!
These links go the official help and training sections of each citation management tool's respective website.
For more help, look for online how-to videos and documentation (particularily on YouTube).
Every manager has a way to export its files or import new files. Search either the manager's website or the web to learn how to conduct the process.
Make sure you know which file types the manager you are importing into can read so you select the right one when you export.