For the average user, the functional differences are irrelevant. More specifically, most people use only a fraction of the capabilities. LO offered DOCX support before AOO, and that was a difference noticeable to most users.
For the hard core devoted follower, there are certainly philosophical differences related to code reuse, and people who care about that have probably already figured out that difference and chosen a side. For the end user, it makes little to no difference. Consider my macro document. Should I set the license such that you cannot use the samples unless you open your project? That is closer to LO than AOO.
Apart from that, you are left with questions such as, do I find a user interface more attractive, a particular feature better supported, or reliability on my specific platform. My parents use what I choose to install on their computers.