both provide much better compression then zip, and when you are compressing large amounts of compressible data that is important. i personally use rar (not win

both provide much better compression then zip, and when you are compressing large amounts of compressible data that is important. i personally use rar (not winrar because i am not on windows) because it also: locks created archive, tests it, and adds a recovery record so if a few bits or even bytes flip it can be recovered. rar also has a ton of options to customize compression like splitting into multiple files (i think 7z does this too as well)