Office 2003 was the last truly good version of Office (in my opinon at least). It worked properly then; without the quirks of Office 2000 (and still works perfectly now, having full compatablity with the new Office file formats via an update), didn't have the deliberately obtuse ribbon user interface - which steals a large chunk of screen space, and if hidden to reclaim that space, requries more clicks than simply having a toolbar did. I fail to see any good reason to switch, as unlike the move from XP to 7, no new features of any consequence have been added, and no (positive) updates in speed or behaviour have been made.
I cannot speak for OpenOffice, as the last time I used it was ~7 years ago - and at the time OpenOffice felt like something from the Windows 3.1 era.
I also cannot speak for LibreOffice, as I have never used it.