Go-OO is a tweaked OpenOffice with various improvements and better functionality.

Better interoperability
Go-oo has built in OpenXML import filters and it will import your Microsoft Works files. Compared with up-stream OO.o, it has better Microsoft binary file support (with eg. fields support), and it will import WordPerfect graphics beautifully. If you are reliant on Excel VBA macros - then Go-oo offers the best macro fidelity too. If you expect your spreadsheets to calculate compatibly, or you get embedded Visio diagrams in your documents, you'll want Go-oo.

Better functionality
Go-oo's user interface is more familiar, with lots of small pieces of polish. We have built-in (working) multimedia integration on Linux, a beautiful solver component, and your Chinese should look sane. We also integrate with your system better by default: eg. enabling native file-selectors on Linux.

A Faster application
From first-time startup, where we sort I/O to reduce seek cost, to a highly optimised second start application and a systray quick-starter on Linux we are faster. We use less memory than up-stream, we link faster, use better system allocators, and don't waste so much time & memory in the registry. Go-oo performance is hard to beat.