alt Hacker NewsOr, when you have a Django project and started out on SQLite, but then begrudgingly introduce M-to-N relationships, but then suddenly notice, that many things you might want to do or implement with those M-to-N relationships are not supported by SQLite. Then you suddenly wish you had started with Postgres right away.
There are definitely some caveats / tradeoffs with SQLite, but I can't think of any that are specifically related to many to many relationships. Which features did you find missing? Lateral joins maybe?