I did it as preparation for my Masters and it was genuinely helpful. Would recommend it to everyone looking to do a prob 201 before taking advanced-ish courses.
I found the EdX course too rushed (assuming you don't pay for the verification to get lifetime access). I like Bliztstein, so I instead used his Youtube playlist [0]. It has his full lectures. Also, his book is free to view [1].
I did it as preparation for my Masters and it was genuinely helpful. Would recommend it to everyone looking to do a prob 201 before taking advanced-ish courses.