Code.org is amazing! I'm a science (biology) teacher who is required to teach programming. The lessons are straightforward and sequential. I picked up the lessons and program in no time at all. I love the teacher side of the site. Very user friendly.
My overall opinion is wonderful. Student-led lets me walk around the room and monitor. Content is well scaffolded. Fast learners can work ahead. students love it. I'd say it's a win-win for teacher and student.
How I Use It
I use this course C for my 6th graders robotics class. Select the course you want your students todo. Add your students name to the roster. And hand them their password cards (auto generated and easily printed). Student login to the website and students teach themselves. If a student's question stumps you, ask another student in the class to help. One of them will know the answer.