The teacher is pretty good – I actually enjoyed watching the lectures and wasn't bored, which is unusual with me when it comes to lectures. I really liked the "optional" videos (watched them all). Not sure whether they would have been taught in the real course, but they add a lot.
It took me, on average, 15-30 minutes per week for the "dry" (problem sets) part, and another 15-30 minutes per week for the "wet" (programming questions) part. This is way, way too little. The exam was extremely easy. It took me less than an hour to solve (out of 3 allotted hours), and the handful of points I lost are due to pure sloppiness (mis-reading one of the questions).
To conclude, I really enjoyed taking the course, and big thanks to Tim Roughgarden and the course staff for offering it and investing effort into making it enjoyable. I will be seriously considering enrolling in the follow-up Part II in late summer.