Repetition queue is the most important feature of MarginNote. It improves retention from 10% to 90%. But it has a slight usability problem:

At the moment, new flashcards are included in repetition queue only when already reviewed once. But I might create hundreds of new flashcards in one session, and later it's impossible to distinguish between reviewed and non-reviewed cards, so I must review all of them to make sure they get to repetition queue.

I suggest to automatically schedule new QA flashcards for repetition.