Personally, I tried the ungraded method for about 3 weeks. It’s great for listening, but it’s not great for writing and speaking. Unless the word or sentence structure is repeated over and over, I can’t remember it.
To be able to remember things well, I need to take notes or pay attention. Otherwise, it’s like listening to a lecture without taking any notes. It doesn’t work very well.
Currently, I’m studying Kanji. I watch the video and at the same time, I try to take some Kanji (even if I take a little too much for my liking). After a few videos, I read the written transcript to test my knowledge of Kanji. It works pretty well.