After trying Things, Omnifocus, The Hit List, and a few others, I switched back to Things. Seems to work the best and honestly, it's the most pleasing UI to look at. Just gorgeous.
I use Apple Reminders because it connects to Apple and Microsoft servers.
As a sys admin I use and manage several systems that include G Suite, Office 365, Trello and others mentioned. Office 365 is the overall best or at least most capable. Office 365 includes Planner.
I'm predominantly using Evernote as well. It works fine, for my needs anyway. I was interesting what other people are using too. Might give some of the other options a go too.
It interests me to read this because Evernote is really a notes system above all, and Wunderlist has been purchased by Microsoft with a lot of good changes happening with Office 365.
To me the best task management systems have good server side and have to be available across platforms. Apple's Reminders app synchronizing with Office 365 or an Exchange server is a good example of that.
The perfect world might be coming soon - taking your Office 365 Planner items personal as "To-Do" app. For now anything To-Do is also going to show up in your iPhone or Mac's Reminders app.