I went from MS Office 2003 to OpenOffice.org when OOo was able to read/write the .doc files I was using. Actually, I was using it before they were saving files as .doc - OOo 1.x??. I was using both Windows and Ubuntu-based OSs at that time so I needed something that would work on both systems. Then just around Christmas I read about LibreOffice coming out with its first public release. I ended up installing the last RC version before the "official" release came out. I un-installed OOo on most of my systems in favor of LO since that point.
Yes, LO is "officially" a fork of OOo, but at that time OOo was a "virtual dead project" with the lack of "support" by Sun. Of course the fact that when LO's first release came out, articles started to show up about how much better Lo was over the "OOo project" and LO was soon the default of a large percent of the Linux distros that came out within months of LO's release - and "dumping" OOo as the default office package.
OOo was stagnant and the people who decided to create a fork of the OOo project and start it moving with the badly needed updates and improvements. So the LibreOffice project took off while OOo faded into the background. Of course then Sun finally decided that OOo was a "dead project" for their company and ended up "selling" it, including the rights to the name, to Apache.
The key to me is not whether or not it is a fork, child, or any other relation to the original OOo project, but the fact that the people behind LibreOffice in the early days decided that they did not want to see the idea of an FOSS office suite package to die do to the lack of "caring" by the one who owns the brand name of the current FOSS package. These people decided enough was enough and started to do the work on the code base and make the improvements needed, without waiting for another 3, 4, 6, or even 8 months till the next version release of the original project to come about. Thank goodness that these people did that.
Now we have a maturing project that has seen 4 years of work. LO has become what OOo should have become but did not and maybe would not without the push from our early developers. There are people who look at both the LO project and the AOo project, both starting from nearly the same point in the code cycle of OOo. I have not read anything where it makes me believe that the AOo project has the "passion" of its users and developers as the LO project has been for the past 3 or 4 years. None of my tech e-newsletters have had articles [so far as I have seen] that talks about the advances in the open source office suite project[s] being part of the AOo suite. Every one of these articles talk about LO advancing the free and open source office suite development and advancing its market share in the free and/or paid office suite market. Every time I read anything about an office suite that is free or one to use instead of MS Office, the name of LibreOffice comes up.
IMO - MS is doing a lot of things with their office suite package lines that lead me to believe that LibreOffice is starting to get some people at MS headquarters worrying about our free and open source office suite package and what will happen to MS's market share as more and more people are going toward free software over MS's paid software.
No matter what LibreOffice is, fork, child, or whatever, there is no doubt in my mind that more and more people are turning to LibreOffice for their office suite needs.