I was in need of a to-do list addon for firefox and this one hit all the check marks.
One of the biggest things I was concerned todoist wouldn't have is sub-tasks, but thankfully they do, allowing tasks to be split into sub tasks that make progress more measurable while staying concise. Overall, a very good addon and if I get a new device, this will definitely be one of the first addons I install to firefox.

After my wife (the organized one of the bunch) died, I was at loose ends. I am computer-savvy (I first ran one in 1963 -- punch cards and all), but I bought my first smartphone then (my daughters insisted) and I discovered Todoist. It immediately let me keep track of ongoing projects, and it got even better when I could use Todoist in my web browser and it automatically synced with my phone.

Even the quibbles don't diminish my five star review:
a) I cannot print the day's requirements directly; I have to use the computer's (MS) print screen dodge. I post it on the refrigerator to help me when I stumble out of the bedroom groggily in the a.m.
b) Why doesn't the web version not allow 1300 in the time box or else have the handy clock hands of the Android app?

Best task manager there is.

This lightweight to do list app packs a big punch. I use Todoist across multiple devices to great effect. The free version has all the features I need. Would recommend.

Useful and I haven't experience any problems.
One little thing though. When I use "Add to todoist from context menu, it adds CURRENT page regardless of the place I clicked with right button. If I am "adding to todoist" by clicking in the background of the current page that's OK. But when I right-click on link and "add to todoist" it is expected to add the url of the link, not the current page. It's how Pocket and internal bookmarks for example work.