Microsoft Office Mac 2011 too buggy on Lion

We mostly use Apple Macs here (except for a Windows XP netbook for some ham radio software). We love Apple's iWork suite but my wife is required to work on documents in Microsoft Word.

She runs Microsoft Office for Mac 2011 on Lion. We have the latest updates of both but her day to day experience is very poor.

The documents she works on are large, hundreds of pages, with track changes enabled and showing lots of history.

Every day, every few hours, Word hangs in some way. Sometimes it shows a black window or a blank dialog box. Mostly we can't quit the program nicely - we must force quit to get out of it.

Word does recover the file without losing too much but it can be distressing for her when deadlines are approaching.

Microsoft do acknowledge quite a few "known issues" but no crashes in Word (only Excel).

This morning, just before heading out the door, we were unable to copy a PowerPoint presentation to a USB key. I know from past experience that Office holds files open even though the window is closed for some reason (no idea if this is still the case but it used to be). We tried to quit all the Office apps, they did appear to exit but when we tried a restart it was prevented by Word.

This software has been around for a long time. People rely on it. I'm embarrassed on behalf of the industry that a user can have such a bad experience every day. LibreOffice is looking very tempting again.