I use LibreOffice but I’d recommend using MS Office if you can afford it.
LibreOffice is quite buggy – not enough to stop you doing your work (generally), but enough to be annoying. Font rendering is all blurry, so it does your eyes in after a while. And while they have added a few features of their own, they have also copied all the worst bits of MS Office. It’s like a fake rip-off of a brand-name product.
Generally I quite like Apple’s Keynote, Pages and Numbers as long as you're not constantly needing to share files with Office users, as long as you accept that they sometimes work in different ways (not necessarily inferior/superior), and in the case of Pages and Numbers might not have all the features you need.