I have File Synchronizer from Latshaw Systems...I tried to use it...but, I didn't like it.
I use Total Commander...it's free if you don't mind the nag screen on Startup.
It has a compare Folder function. Just put one Folder on the left Panel and a different Folder on the Right Panel and click COMPARE.
It highlights any file that is different in RED. Then, just click COPY. Folders are identical.
http://www.ghisler.com/