Since the OP specifies Mac users, as a Mac user, I find iWork perfectly serviceable. I think it's a bit controversial with its "Ribbon" on the right rather than the top, though it kind of makes sense. I don't love iWork (Writer, Numbers, and Keynote), but they are good and they come with Macs (or at the very least are free in the App Store).
I have tried LibreOffice recently, and I didn't care for it. But I am glad that such a robust free office suite is available on Windows. I believe some Linux distros ship with it, too. If I didn't have iWork, I'd probably just use LibreOffice. It's not terrible, I just have a better choice.