I'm a big OpenOffice advocate, been using it for years now and even got my kids using it. Stopped paying MS for their Office around the '97 version, done with that noise for what little I need.
However, I'm on the fence now as LibreOffice, the OpenOffice spin-off, seems to be advancing much faster and becoming more widely adopted than OpenOffice.
Not like it really matters as I downloaded and installed both, not like it cost me anything other than a couple of minutes of my time.
If either have a problem I can easily switch to the other and see if it works better! ;)