From Dag Agren:
The Unarchiver supports more formats than I can remember. Zip, Tar, Gzip, Bzip2, 7-Zip, Rar, LhA, StuffIt, several old Amiga file and disk archives, CAB, LZX, stuff I don't even know what it is. It copies the finder file-copying/moving/deleting interface for its interface and uses the character set auto-detection code from Mozilla to auto-detect the encoding of the filenames in the archives. The Unarchiver supports split archives for certain formats, like RAR. It is built around libxad. This is an old Amiga library for handling unpacking of archives. It supports a whole lot of formats, and I added a couple more, and bugfixed old code. I also wrote a higher-level Objective-C wrapper around it, which might be useful for other projects too (including Xee).
What's new in this version:
Fixed spurious error message when extracting multi-part RAR files.