NeoOfficeJ is a java implementation of the OpenOffice.org suite of business programs. It is designed to take advantage of the OS X specific tools and interfaces. I find it to be a very useful, powerful program. I haven't used the spreadsheet much, but it does seem to be adequate for most, if not all, basic spreadsheet needs.
I have looked at the database functions, and superficially at least, they look very much like MS Access. So, it appears to be a relational database. However, I have not tried to develop even a simple table, so can't give a review of this function.
There is a presentation manager, a drawing program, and even HTML filtering and authoring tools.
Finally, since it follows the OpenOffice.org format, it is fully customizable in every way. You can even get the source code in order to rewrite the whole thing, if you really want to.
I highly recommend this program.
Now, as to why I use this, instead of OpenOffice.org - OpenOffice is written specifically for XWindows, (X11), and doesn't take advantage of the OS X interface. It is also huge, slow, and clumsy compared to NeoOfficeJ.
The first beta release of NeoOffice/J happened on December 21, 2004 and was known as NeoOffice/J 1.1.