OpenOffice.org was once the open-source office suite of choice, but it fractured into two separate projects — Apache OpenOffice and LibreOffice. Never mind Oracle Open Office, which was actually a closed-source office suite and was discontinued.
It doesn’t really matter whether you use LibreOffice or Apache OpenOffice. Both are good choices if you’re looking for a powerfulfree office suite. The two projects are so similar that you’d be unlikely to notice the difference.
We’d recommend LibreOffice if we had to choose one of the two. It’s seen the most enthusiastic development and has the most potential in the long run.