cPanel and Plesk are both excellent control panels, and you should base your choice on your personal preference.
Plesk has a simple GUI with each category laid out as navigation menu items in the sidebar. While cPanel categorises the various groups and provides a search function.
Generally, cPanel loads faster and is quicker to navigate around than Plesk. Both control panels provide the same primary features for users including email accounts, file manager, FTP access and more.