Pages and Numbers definitely aren't as fully-featured as Word and Excel but whether that is a problem depends on what you do! Definitely give them a try, and be prepared for some things to work differently to their Microsoft counterparts – the temptation of course is to assume that “different” = “wrong” but sometimes, after a bit of effort, it turns out to be better.
In terms of functionality, I'd say Pages is somewhere inbetween Google Docs and Word. I think Google Docs is terrible for its lack of features, but many people have very simple needs and think it’s fine. Pages is definitely a step up. I’d also argue it’s better than Docs/Word if you want to lay out posters, leaflets etc. as this can be really frustrating with Docs/Word.
Numbers does seem fairly basic, although I haven't used it a lot. Excel for Mac isn’t as good as the Windows equivalent but again, you'll only notice this if you rely on particular advanced features.
I tried LibreOffice once. There’s a reason why it’s free. It's massively ugly and worse, crashes all the time. The user manual is a poorly written Wiki page and if you need any help, the suggestion tends to be to rewrite the code yourself as though everybody is capable of that. Having said that, the regular expression feature in the Find and Replace of their Excel equivalent is handy if you need to do a lot of text cleanup!
