OpenOffice.org - #1 Free Office App
Without a doubt, on virtually every platform, the number one free office program is OpenOffice.org. Matching Microsoft Office in many important respects, this platform is available for Mac OS X, Windows, Linux, and Solaris. It achieves this incredible cross platform compatibility by being written almost completely in Java.
OpenOffice.org has all the components of any solid office suite. Writer, equivalent to Word, enables people to create documents and has a basic WYSIWYG editor for web pages. Calc, the Excel equivalent, has the vast majority of Excel functionality; however, from my experience it is much slower than Excel when loading large files. As such, you might find either Excel or Numbers to be better if you’re looking to edit large spreadsheets. Finally, the OpenOffice.org equivalent of PowerPoint is called Impress and, although it lacks many of the templates that Microsoft’s or Apple’s presentation software has, it performs very similarly to the aforementioned applications. If you’d like to read more about the parallels between Microsoft Office and OpenOffice, there’s a great article on Bright Hub that provides more detail.
My personal experience with OpenOffice has been positive. It lacks a lot of the glamor and pizzazz that the commercial suites have, but there are many times when I’m pleasantly surprised by its depth. I can’t tell you the number of times I’ve been both amazed at how much of the functionality has been duplicated, but also disappointed that the interface for that functionality hasn’t been more refined. All things considered, for the most part its excellent free office for Mac software.