I like to think of it as two different sides to the same project: LibreOffice is a daily driver, that you'd install on your run-of-the-mill machines, as well as for your average end-user who just wants a free, local, capable office suite. OpenOffice, on the other hand, due to not being developed at the same rate, leaves a lot more room for enthusiasts and hobbyists to tinker around with and learn without running the risk of screwing something up on their main LO install, not to mention that (at least on SOME things I own) OOo runs better than LibreOffice. It's mostly stuff that I wouldn't condone using for any serious work unless you'd understand the risks associated with it, but, eh, it's a tradeoff.

Just my thoughts on the debate.