OpenOffice entered my office February 2004, as the computer I am writing this with only came with Microsoft Works (I did not want to pay full retail for Microsoft Office while I am still starting up the consulting business). OpenOffice V1.1 just works for what I do — make resumes, some letter writing, and some short documents for my consulting business and my wife and daughter's schools.
Speed is quite good except for program startups (but I am being spoiled by the (nearly) instant-on nature of my older PalmOS PDA). I have not seen any problems with document compatibility between OpenOffice and Microsoft Word; I use the OpenOffice word processor to do all my conversions of text and HTML to Microsoft Word.
I found my first defect today — chart text reformatting can squish your chart labels if you are not careful (I finally generated both charts after several retries).
OpenOffice V1.1 is well worth a look for those wanting an alternative to Microsoft Office, especially an extensible and Open Source alternative.