Although I use the Apple apps on my devices, they access Google services, which I tend to use, and prefer – a long-term use choice.
Mail – all accounts are linked to Apple mail app. I cannot stress enough how beneficial it is to aggregate multiple email addresses into one app (or client if you’re on a desktop/laptop) – makes tracking and archiving youre mail so much easier.
Calendar – linked to Google Calendar. This enable me to share calendars with other family members and be able to put events into different categories.
Contacts – linked to Gmail. As above. We share one set of contacts between us using Google Contacts but linked to the Apple Contacts app.
Notes (EverNote) – I used to recommend EverNote and there’s nothing wrong with it at all. I think a good note-taking app is essential an just the place to add quick notes, link to audio/voice memos, etc. Apple have improved their app significantly so it’s just more convenient (and cheaper) to use it. I can share Notes using iCloud.