WinMerge is an application that can compare different folders and files and will find differences. Based on differences found, you can perform different actions in order to keep your files updated.
Is able to compare content of files and will display differences with a color. Also, can includes subfolders and their content in file comparison.
Includes an option to synchronize folders or files based on differences that has been found. Interface includes tabs and dual panels, so is easy to use.