Once you graduate or separate from UNC Charlotte, the EndNote software and your libraries will remain on your desktop. You will no longer, however, have access to any software updates. You will also be able to keep your EndNote online references, as EndNote online is already a free citation management software. You will have the full number of styles, filters, and connection files online for one year after your last onsite logon to EndNote online from within the UNC Charlotte system. After that time, references and attachments will remain, but the number of styles, filters, and connection files will drop to the basic or "free" version's amount, which is much smaller. The data will remain, though. Should you wish to buy a private copy of EndNote, you will be able to sync all your references from Endnote online--with all groups, group sets, and attachments, to an empty library in a new copy of EndNote.
Here is a comparison done by Johns Hopkins University & Medicine Welch Medical Library of several major citation management softwares: https://browse.welch.jhmi.edu/comparison-of-citation-managers/chart
Here is an extensive comparison done by Wikipedia: http://en.wikipedia.org/wiki/Comparison_of_reference_management_software