Contrary to popular belief winzip is not free. Since the ability to read a ZIP file is natively a part of Windows many of us will never need winzip. As the Linux and Windows worlds are slowly starting to merge you may find yourself needing a program that can extract file from TAR or GZIP.
If you ever need to create a archive then this is the way to go. Since this is open source it will likely be with us for a long time. The interface is simple and I find it just as easy to use as winzip.
From below you can see they also claim better compression ratios as well.
Hint: When sending a ZIP or EXE file in email you can bypass the filters using the .Z extension and the windows operating system will still associate it as a ZIP file.
The main features of 7-Zip
High compression ratio in new 7z format with LZMA compression
Packing / unpacking: 7z, ZIP, GZIP, BZIP2 and TAR
Unpacking only: RAR, CAB, ISO, ARJ, LZH, CHM, Z, CPIO, RPM, DEB and NSIS
For ZIP and GZIP formats, 7-Zip provides a compression ratio that is 2-10 % better than the ratio provided by PKZip and WinZip
Self-extracting capability for 7z format
Integration with Windows Shell
Powerful File Manager
Powerful command line version
Plugin for FAR Manager
Localizations for 63 languages