Ask HN: What's to like/dislike about MLT framework? (non-linear video-editing)

There seems to be vocal opinions[0] on scalability/stability issues with MLT[1], which powers a fair number of OSS video-editing applications like Shotcut, OpenShot, Kdenlive, Flowblade, etc. I've enjoyed using it, and haven't personally seen any scalability issues. Am I missing something? Is there something "wrong" or limiting with MLT for particularly large projects? Or, are these issues more related to the applications and implementations? Save for MLT, what other options are out there?

[0]: https://news.ycombinator.com/item?id=16280788

[1]: https://www.mltframework.org