WinRAR can create multiple-volume archives (popular with file sharers) and use 128-bit AES encryption to password-protect them. Like most of its competition, it also has an option to hide file names inside an encrypted archive: someone without the password won't even see what files you've archived, let alone view their contents.
In our maximum-compression tests, WinRAR 3.61 archived our files faster than most competitors; except for StuffIt Standard 9.5. Though we found .rar archives to be smaller than conventional .zip 2.0 archives, they weren't as small as .7z files created by PowerArchiver 2006 and ZipGenius 6 Standard or .zip files created with WinZip 11's new Best Method option.
Like most other file compression programs. WinRAR can also compress .zip 2.0 files, hide file names, and split archives into multiple files of user-definable size.
WinRAR boasts some powerful automation tools--surprisingly so for a program in this price range. After you've set up an archive job in the incredibly powerful but intimidating six-tabbed 'Archive name and parameters'' dialog box, you can save those parameters as a profile for future use. That lets you, for instance, simplify an incremental backup by creating the appropriate profile (among the relevant options you'll find among the tabs are ones for backing up only changed files and for shutting down the computer when you're done).
You can automate chores even further with WinRAR's powerful command-line parameters, which let you create Windows shortcuts and old-fashioned DOS-style batch files to do particular jobs.