I remember being both Neil Cummings and Max Schwarzmueller courses to be good, but I did them some time ago and when I was never to web development.
There was a Python course offered by three profs at Rice University that was A+.
Similar for Dan Ariely's Behavioral Economics class - of course, maybe it was all lies (now it turns out), but entertaining nevertheless.
Andrew Ng's course is quite math-heavy (I haven't done it), but it gets rave reviews.
So many Coursera tech/CS courses are offered by profs at elite universities - there's no way they could be the kind of crap that is standard on Udemy.
What Coursera lacks (compared to the university experience) is personal interaction with a real professor, group projects with smart and focused classmates, and personalized feedback.
But the few times I started a Udemy course, every single one was terrible, once I got past the first 20% or so. And contrary to their advertising, they did not allow me to return the course, because I had "completed too much" or something. IIRC I was around the 30-35% mark.
Totally different from Coursera, which can be hit and miss, but best stuff is very good.
Have you had a different experience? Which courses did you complete that were good?
TLDR: Udemy - cheap, and you get what you pay for.