I really don't get the enthusiasm for Things 3 in the comments below... It's a nice Todo list, that's all — ok, I'm not a power user and I don't need mobile sync. ;-)
The Tags button has gone away, the sidebar distinction between projects and areas too, except for their icon.
Things 1 and 2 were a bit clearer, I think, but Things (any version) lacks colours! Nothing beats the old Finder style underlining colours for making an item jump to your eye, whatever its position in the list.
One nice feature is the dark mode, though.
But for the price, I'd expect a lot more options (colours; may be varying colours from green to red when the due date becomes nearer, etc.)
I haven't found a much better alternative and I think, all in all, that there's not a lot of imagination deployed in the Todos business... ;-)