Been using Anki on and off for years for learning Japanese and more recently, have been using it for studying for university courses.
It’s a great tool, but it’s definitely got some oddities, like how its editor has every formatting and templating tool under the sun but is somehow missing spell check, how some features can only be had through fragile extensions, or how for some reason it’s one of the few programs one shouldn’t install from their distro’s package manager.
One of these days I’d like to take a crack at building my own cross-platform subject-agnostic SRS card app. There’s a number of things I’d do differently.