I answered a post about favorite calendar systems in the following way.
I use an Android Phone so I can google everything. I won’t use an calendar app that does not sync with google cal. and tasks. On the phone I use gtasks for tasks. Google cal. is easy because I can create as many different calendars as I like, (work, personal, kids, bills) and each displays as a different color. The biggest problem i have is no matter what calendar or task reminder I use I have ADHD and therefore the real struggle is to look at it first thing and before making commitments. I have managed to find a way to avoid every reminder but having it is much better than not.