All of these programs accomplish the same thing -- help you create a database of citations you have read or want to use in a paper (or both) and work with your word processor to insert the citing information into your paper or manuscript.
In addition to being a time saver, effectively managing your citations helps you cite your sources and keep your research organized, and avoid accidental incidences of plagiarism.
My Favorite tips (from the brochure) are the ones they give for paraphrasing.
Whether you use one of the listed products or one of the many others, using a tool to collect the citation information for articles, books, or websites you are reading will pay-off when it is time to right your paper. In addition to collecting information, it can help put out that information into your manuscript - both in the text and in the reference list - AND in the format of your choice. Yes it takes a little learning to be efficient with these tools, but it is time well spent.
I am available for group workshops on EndNote & RefWorks. I can also offer individual consultations on any of these 4 programs. Just contact me and we can arrange something. See side box for contact info.
For local support, you can use the Ask a Librarian service (we have both email and chat options).
Online tutorials may also be helpful and I've linked to a few below.