NeoOffice/J is a really clever hack: Patrick Luby and friends have used Java on Mac OS X to remove the X11 dependencies from OpenOffice.org version 1.0x.
No X11, native fonts, etc. I only used NeoOffice/J to edit some existing word processing and diagram documents - I saw no problems what so ever. Very cool.
One huge advantage of NeoOffice/J and OpenOffice.org is the universally open and readable XML format. XML files for a document are conveniently stored in a single ZIP file.