These days, cross-platform .zip compression is built into Mac OS X, our networks are faster and storage space is cheaper. So is StuffIt still worth it?

The answer is no, despite the improvements made in how StuffIt compresses files. It could do this because JPEG compression is a two-step process.

First, the picture is broken down and reencoded in a different way, throwing away info that we don't miss, a step called lossy compression. Then the reencoded data is itself compressed losslessly. It's this step that the StuffIt engineers have improved so that they can offer increased compression ratios without further data loss.

In the last release, Smith Micro added the ability to compress JPEGs even further with no loss in quality. In our tests, we saw StuffIt outperform OS-native compression by around a quarter with JPEGs, where the native ZIP compression had only saved a little over 1% of the raw file sizes.

Version 12 adds the same support for MP3s and PDFs, but performance here is less impressive. PDF compression using the .sitx standard saved only 3% more space than OS X's .zip, and neither did well when compressing a selection of MP3s; a 2.7% saving by the OS, and a 3.2% saving by StuffIt.

There's lots more richness to StuffIt - the ability to split archives into chunks to fit onto a CD, say, as well as the option to automatically upload archives to an FTP or .Mac server, and the ability to create and decompress a wide range of archives and encoding methods. But it's slow with large groups of files and a little pricey. Worse still, it crashed when compressing a mixed selection of files, whereas OS X's own system performed fine.