[bachmeier]

Todoist is currently the best option out there. I have a Premium subscription and recommend it to everyone, in spite of the free alternatives (which on my campus includes MS To-Do, since Office 365 is provided for free).

Having said that, it's not perfect. You need to be prepared for some frustrating bugs in the web app. That includes having been unable to log in on my laptop for several days. Todoist gets updated too frequently relative to the ability to test for and identify bugs. Finding that a pile of my tasks were marked done was not a moment of joy, and having items scheduled for the wrong day wasn't a great experience either. That Todoist is easily the best option is a function of the low quality and excessive prices of the competition.

[amix]

Hmm, these are some serious issues, and they should not be common at all. I hope you have reported them to our support team ([e-mail]).

[bachmeier]

Yes, I've been reporting most bugs as I encounter them.

(Just realized amix is Amir Salihefendić. I thought it was a Todoist employee, though rereading the OP it should have been obvious.)