At what point will LibreOffice and OpenOffice diverge far enough for LibreOffice to stop adopting the improvements OO creates? At what point will these projects truly diverge? Until then, I see little reason to use LibreOffice instead of OpenOffice, besides on philosophical grounds.
LibreOffice already includes multiple patchsets (what used to be go-oo) that have been rejected by OpenOffice for political reasons, so that's one reason. Most of the non-Oracle developers on OO are now working on LO, so I don't see any reason why the codebases would have a huge divergence in the near future other than intentional mucking-up by Oracle. Of course, one day LO may decide to take things in a direction different than OO or vice-versa, but there's no point in that kind of speculation.
Cue criticism of name
worth downloading just for the increase in max number of rows in Calc, imo.