I personally much prefer Udacity's format--short videos (30 seconds to ~7 minutes) with a question after most of them, and then an explanation video. The Coursera courses I've seen have 15 minute videos/1 question, so I don't find myself retaining the material as well.
Moreover, Udacity (atleast for CS373) asks programming questions as quizzes, so you have more exposure to the programming rather than just the theory.
I don't know if this will be as bad for a compilers class, but CS373 definitely let a lot of the math be magic versus Coursera's Machine Learning class.
Like you I plan to try both of them and ideally finish both of them. I am also waiting on them to announce a part 2 of the Data Structure and Algorithm class.