I have submitted “Feedback” to Apple’s Map section about the importance of including speed limits but am not holding my breath.Last year I was at a seminar where several map providers reported how advanced they were with this:
http://www.globalncap.org/wp-content/uploads/2017/09/Seminar-on-ISA-systems.pdf
I used to prefer Google Maps for travelling around Australia but it now seems less user-friendly (maybe because I refuse to log into my Google account) so I am more likely to use Apple Maps. In any case, phone coverage in rural Australia is woeful so I rely on offline map apps like Metroview and Sygic (for New Zealand). Both have reasonable speed limit data.