While there are free, dedicated utilities for unarchiving things like 7-Zip and RAR formats, it's nice to have one tool to rule them all. BetterZip handles multi-part RAR files with finesse. I don't deal with a lot of files in these formats, but on the occasion that I do, being able to display the full contents of the split archive and pick and choose what to extract is a useful trick.

Another area where BetterZip shines is with problematic archives. Have you ever had a zip file that wouldn't unarchive when you double-clicked it, instead throwing an error about permissions or some less-descriptive number? BetterZip rarely fails me on those occasions, I just do an "Open with" on the file, load it up in BetterZip, and the problem is solved. I can drag a selected file out or unarchive the whole thing to disk. One of the causes of errors I sometimes get is the archive being password-protected. OS X doesn't tell me this, it tends to just fail when it tries to unarchive the file. BetterZip has the common decency to offer me a password dialog.

BetterZip is US$19.95, with a free trial available at the developer's site. A competitor, Springy, can do many of the same things for the same price, but I prefer BetterZip's layout and aesthetic. If you're in the mood for a side-by-side comparison, Springy has a free trial available as well. If you just want to unarchive various formats not supported natively by OS X, The Unarchiver is a free utility you should take a look at. I'll also mention sArchiver, a Java utility with similar functionality for $15. Again, the extra $5 is worth it to me for the more Mac-like experience provided by BetterZip. If compression and archiving are part of your everyday life, a utility like one of these can definitely be a lifesaver!