I have been using Beyond Compare 2 for a two or three of years now. It is the best $30 you will ever spend for computer software if you work with files on a daily basis. I can’t say enough good things about it. It allows you two compare and merge files and directories on local, UNC paths, and even ftp. You can specify exactly how you want to treat orphans, differences in files, exclude files, etc. You can even define rules as to how the content of files should be treated. For example, is white space important. The easiest way to compare two files is to right click the two files you want to compare, and it will open up Beyond Compare 2. You can even script everything with its very easy syntax. I use it for backing up my files to a backup share every night. It supports copying and synchronizing. You can do so from left to right, right to left, both directions. It is truly a powerful and easy to use interface for synchronizing changes at the file and directory level. If you work for a company that needs bulk licensing, unlimited, or global licensing they have extremely nice pricing for bulk customers.