StarOffice 5.x had some quirks, but most could be configured away, and it wasn't more memory hungry (or even just slower) than the successor OpenOffice, either, which used much of the same code. It also wasn't a Java application any more than OpenOffice/LibreOffice is*, and it wasn't any more 'monolithic', either. The difference was purely visual, it just used a common multiple document interface for all of its document types, not senselessly duplicating menus and function buttons and other controls for each document, thereby cluttering the screen more than necessary. Also, StarOffice 5.x included a calendar and a full-featured e-mail and usenet client. When everyone was exepcting that they might make all of that, including mail and calendar, just a little bit more Microsoft compatible in one of the next versions, so that it could actually become a drop-in replacement for Office and Outlook, the company was sold to Sun where it was cut down to the sorry remains that became OpenOffice 6. To do justice to Sun, if I remember correctly, some parts of StarOffice 5.x would have been more difficult to keep than others because they were licensed from others by StarDivision, the original company, and couldn't be made open source.
* Just before StarDivision disappeared and StarOffice was replaced by OpenOffice, there actually was a pure Java *version* of StarOffice, and it was a brilliant piece of Software, with two parts which optionally could be installed on two different machines and distribute load between both (client/server). It never was publicly available, but I've seen it in use once back then, and it looked great and seemed to work great, too. It was actually in commercial use at a big German internet services provider/web hoster as an early predecessor of what now is the LibreOffice-based 'Collabora'.