Now, you get what you pay for, and these courses are free, so I will not complain about them in the way one would if paying. In fact considering they are free they are absolutely incredible. I don't know of anything else you can get for for nothing in this world that is so valuable. (Don't say "love", you know what I mean!).
But let's tell the truth, some are better than others. Some professors are better speakers than others, some material is deeper, some lectures longer, and so on.
My particular observation here is on two courses on the same subject. I will go further than not naming names, publicly, I will not even mention the subject. I do now wish to show ingratitude to those who have freely given their time to offer the poorer example.
But the difference is profound.
In the poorer course the length of each video is shorter, and the number provided each week is less. Therefore the amount presented is less. It becomes a "skim". It appears that to make up for this in some way, the instructors decided to talk faster, and this must be extremely difficult for students for whom English is a second language. Subtitles are provided but are not always correct.
In the better course the professor appears more relaxed, perhaps age and experience count for something here, but the effect is to slow everything down. His presentation style is more natural, and the structure is very cleverly done, each week one lecture is an overview, then each point is covered in more depth in the rest of the week's material.
When it comes to the tests, there is no comparison. The questions in the better course are not ambiguous. Provided you paid attention and took notes, they can be answered. In the poorer course, despite multiple choice answers being offered, and watching one particular video 6 times, I still couldn't decide on an appropriate answer. And.....I don't think the problem there was me, frankly.
I have seen some complains on discussion forums about lack of instructor activity in the forums. That they have time to visit them AT ALL is remarkable. That anyone complains about this.....well, some people want blood from a stone. From the start I expected only peer support, it's really quite enough. So I would not assess a course on the level of instructor support.
There are a few students whose complaints are considered unjustified by other students, are told pretty much "if you don't like it, go" in no uncertain terms. I was then shocked to see many, many comments of "I can't find how to drop out". Somehow they managed to sign up, but cannot figure out for themselves how to leave. I'm not really buying it. I think it's an attention seeking device.
EDIT: Final week of the poorer course was excellent. So, it really does depend on the professor.