Open archives in a wide range of formats, including ZIP, RAR, 7Z, TAR, SIT, 7-Zip, 7zX, iShrink, SimplyRAR, Rarify, SITX, Keka, iArchiver, etc. Extract files from protected ZIP archives encrypted with 512-bit or AES 256-bit algorithms. Get the Growl notifications or an email when the process of decompression is over.
StuffIt Expander is a very powerful archive decompression tool. It looks a bit deceiving, and I bring this up because when I first used StuffIt Expander I didn't think much of it. The application's main window is very small, with only a few buttons, and I was JUST making the switch from Windows, so I was accustomed to using WinRAR, WinZIP and the like. Those apps pop-up a window when you open an archive, and they often show warnings and errors. StuffIt Expander does none of that. It does one thing : takes files out of archives. So, by dragging, for example, a RAR file onto the main window, StuffIt Expander automatically uncompresses that archive. By default, the files are uncompressed onto the same folder as the archive, but you can customize the app to place folders into other folders as well.
The file format support of StuffIt Expander is impressive. It supports all the most popular formats. It has support for password-protected files, sequenced files and more.
Uncompressing files on Mac is a totally different experience. You simply uncompress a file and its contents are automatically placed wherever you like. I associated all archive files with StuffIt Expander, so I can simply double-click a file on the Finder and it will automatically be uncompressed. I even set the app to delete the archive after it has been uncompressed, so I don't have to worry about that.
StuffIt Expander is free for download but it also comes as a part of the StuffIt Deluxe suite. These days I think the best two apps for uncompressing files on a Mac are The Unarchiver and StuffIt Expander. They both work equally well and you can't go wrong with either of them.