Based on the OpenOffice code, StarOffice has complete Aqua gui and uses all available OS 10.4 capabilities, including access to AddressBook data. Biggest difference between StarOffice and MSOffice is the price. StarOffice is said to include VBA capabilities but I did not see that in a quick perusal of their site and that may only apply to Windows, anyway.
Biggest difference between OO and SO is the interface. Biggest difference between OO, SO and NeoOffice is standards and licensing methods. I think it's good news that there is increasing and strong support for the OpenOffice concept and now better Mac support as well.
Still
way more power than I'll ever need/use!