RYAN CUTHBERTSON  Doesn't feel like 2.0 software. Eg. you can't rename files in the archive, no viewing inside folders in the archive, can't have more than 1 zip file open at a time.

Springy or BetterZip look better. I know they're shareware, but Springy doesn't nag you for being unregistered.  
(Version 2.1.1)

ANONYMOUS  Haven't used it, but considering that all of these compression formats are available at the command line, I'm not sure of the value. The command line isn't as scary as you'd think and "man zip" and "man tar" will give you all the use info you need. One thing to be careful about is when compressing multi-forked files (files with data and resource fork), because depending on your version of OS X, it may handle things badly.  
(Version 2.0.1)

ANONYMOUS  Not too bad of an app. The interface is clean, and the icons look good. I am hoping that future versions of this product will include more features.

Suggested features are

1. Be able to add either multiple files and/or folders at the same time with the click of only one button. RadicalSqueeze has two different buttons, one for folder selection, and another for file selection...and only one file or folder at a time.

2. A preferences pane would be nice to adjust whether to zip or tar instead of being asked every time.

3. Show the archived file in the Finder when complete.

4. RadicalSqueeze-specific file icons for .zip, .tar, and .tar.gz.

5. Be able to drag and drop a group of files onto the RadicalSqueeze icon to automatically launch the application and archive the files.

All and all, not a bad application, but it lacks the customizability that some users (such as myself) would enjoy to have. But if you do not care so much about having all the power, and just want to get the job done, then this application should work pretty well for you.  
(Version 1.0)

JIMW  And it probably does a good job at it too, most likely interfacing I guess with the built in command line Unix utilities already built into OS X. So this may only be a GUI (Graphical User Interface) for something you already have but don't know how to use because it is not very user friendly and is designed for computer engineers. In Panther Apple does provide ZIP but not the rest.

FYI, If you have a previous version of Stuffit, they regularly have "specials" for $29 upgrades to the latest version of 8.02 which include all of the formats of RadicalSqueeze and a lot more with contextual menus, Magic Menu, Stuff and Mail ,Self-Extracting, BinHex, MacBinary, LHa, Bz, Stuffit and UUEncode by just renaming, encryption, etc. Anotherwords, Stuffit does it all with a better interface for another $15. This seems like a lot better value to me and includes formal support.

in my opinion, given its current feature set, at a $15 price point, this product does not represent good value, no matter how well it might work, given what else is already in the marketplace.   
(Version 1.0)