Planamesa Software has released NeoOffice/J 2.1 Patch 5, a Mac port of OpenOffice 2.1 using a Java-based GUI.
After countless hours of performance analysis work, we recently had a breakthrough that enabled us to identify specific performance bottlenecks in NeoOffice's underlying OpenOffice.org code and fix those bottlenecks by replacing the OpenOffice.org code with code that is optimized specifically for Mac OS X.
As a result of our fixes, image scaling and drawing speed has been increased and memory usage has been reduced. While users may not notice much change in performance when using text-based documents, users should see image-intensive activities such as running a slide show with transitions or scrolling through large documents perform several times faster than before.
NeoOffice is catching up to Microsoft Office, though it's certainly not there yet, and I'm not sure it will ever get there. (Various look-and-feel bugs I've filed have been closed as won't fix.) Mac OS X 10.3.9 or later is required. NeoOffice is published exclusively under the GPL.