This is a matter of debate, depending on what circles you're traveling in. If you're working in a "mixed environment" where some people are using OpenOffice and some people are using Microsoft Word, you're likely to run into problems that range from minor annoyance to show-stoppers very quickly. Some of this can be blamed on Microsoft's weird file formats, but this is true not only for .doc files but for the better-documented (if arcane) .docx and, in my experience, even with RTF. I'm in contact with a fair number of small-to-medium press fiction editors, and while a fiction manuscript is one of the simplest use cases you can imagine in terms of formatting, almost every editor I've talked with has complained about OpenOffice (and to a lesser degree LibreOffice) screwing up comments and revision tracking. I don't really want to use Microsoft Word, but so far I haven't found an open source equivalent for my needs that is good enough. (The closed source Nisus Writer Pro and even Apple Pages seem to do better, ironically. But that's not to say they don't have their own problems.)
I tend to think of open source's most well-established terrain as languages and server-side components where UI is not really a major issue.
The fact that 90% of the world is using Microsoft's format is certainly relevant for everyday use, but it's orthogonal to the question of whether an open source project can achieve feature parity with a closed source product.
File format compatibility is always hard and I'm not convinced MS does a better job reading odt than LibreOffice does with OOXML. But LibreOffice does have a reasonably comparable feature set, even if the UI is not as attractive.
> LibreOffice does have a reasonably comparable feature set
Pile up all the features Office has but LibreOffice doesn't on one side, pile up all the features that LibreOffice has but Office doesn't on the other. What pile's larger?
It's kind of a pointless argument over whether or not LibreOffice has ENOUGH features; enough features for who? It's a global question with local answers. It's pretty easy to count who has MORE features, though, and Microsoft Office wins there.
GP was suggesting Word's superiority comes from its ability to read its own file format, which certainly makes it superior in practice, but has little bearing on OSS vs. closed source.
But, FWIW, most of the new "features" Microsoft adds to Word seem to be UI improvements (e.g. https://support.office.com/en-us/article/What-s-new-in-Word-...). And if you want to claim that Office is more usable than LibreOffice, and that this is generally true of closed source vs. open source projects, you won't get any arguments from me.
This is a matter of debate, depending on what circles you're traveling in. If you're working in a "mixed environment" where some people are using OpenOffice and some people are using Microsoft Word, you're likely to run into problems that range from minor annoyance to show-stoppers very quickly. Some of this can be blamed on Microsoft's weird file formats, but this is true not only for .doc files but for the better-documented (if arcane) .docx and, in my experience, even with RTF. I'm in contact with a fair number of small-to-medium press fiction editors, and while a fiction manuscript is one of the simplest use cases you can imagine in terms of formatting, almost every editor I've talked with has complained about OpenOffice (and to a lesser degree LibreOffice) screwing up comments and revision tracking. I don't really want to use Microsoft Word, but so far I haven't found an open source equivalent for my needs that is good enough. (The closed source Nisus Writer Pro and even Apple Pages seem to do better, ironically. But that's not to say they don't have their own problems.)
I tend to think of open source's most well-established terrain as languages and server-side components where UI is not really a major issue.