Eugene Abramchuk completed this course, spending 12 hours a week on it and found the course difficulty to be hard.
Easily best course I've ever taken!
Reasonably hard, no background needed (some high school math and familiarity with programming is a plus) and Dan Klein / Pieter Abbeel led it in such a fun way, that I could not wait for the next week's materials.
The downside for me was that it was rather time consuming: by the middle of the course I spent about a 1-1.5h on workdays and took one whole weekend day for the course tasks.
It's very sad they discontinued the course.