Yeah I like the GNOME calendar and it works well with Microshit Enterprise accounts if you set up the account in Evolution + Evolution-EWS (if the admin has blocked IMAP etc access so you need OAuth). Thunderbird + Tbsync is my go-to though.
I had a Lumia with Win Phone (I forget the exact model & sw version) and thought it was great - it was super fast, lightweight and the battery life was decent but there weren't many apps out there, at least not in comparison to Android
I always find it amazing when you hear these insights into the downfall of once huge companies. It's incredible how terrible some people's judgement can be and a lot of these successful people are riding on luck rather than intelligence it seems