Libre Office corresponds with M$ Office nearly 1-to-1 feature-wise.

I’ve never seen a single person react to it’s apps as being unfamiliar or different, especially considering the variety of UI shifts M$ Office has displayed since Office 2k. If you were referring to some specific API and integration with Sharepojnt or something I might understand your trepidation, but as your question stands, I have to say that I can’t think of a specific downside to it.

I suppose that deciding upon an output format that you will send out to clients or suppliers will be your main concern, as you will essentially choosing which version of M$ Office you are pretending to be. I find that the older pre-xml format is more universally supported but YMMV