I've used OpenOffice but I don't think my parents would really dig it. It never seemed quite as polished to me. They don't mind paying the money, I just didn't want them to fork out $200 if they could easily get it for $100.
When Oracle acquired Sun in 2009, they ended up stuffing up most of the Sun open source projects... Libre Office is a fork of OpenOffice and being actively developed unlike OpenOffice.
There is some hope for OpenOffice As recently Orcale donated the code and rights to the Apache Software Foundation but right now Libre Office is at 3.4.x where as OpenOffice is 3.3, there has been a ton of improvements.