I haven't tried them yet. I thought it would be interesting to reflect on the latest addition to Khan Academy before I actually did the tutorials, and then see how my opinion differed afterwards. If the write-up by John Resig, the guy who lead the initiative, is any indication, I am guessing I will like the new computer science content very much. Which is good, because I haven't been all that impressed with Khan Academy thus far.
Based on Resig's description, here is what I'm excited about...
Easy to get going. Everything works in the browser, so there's nothing to download or install.
Side-by-side coding and output. You write code on one side of the screen, and you see the results immediately on the right. This reminds me of languages like Scratch and Blockly.
Live updating. When you make changes, the program doesn't start again from the beginning; the changes are reflected in the output right away. This also reminds me of Scratch, and has been something I tried to take advantage of in my programming workshops.
Helpful error messages. "We build off of the existing linting that we do to try and provide extra
levels of hinting. We do spelling correction, provide argument
suggestions, and try to make suggestions for common beginner mistakes." And the errors are apparently shown with a cute cartoon character, making them less intimidating.
Collaboration and community. Although more inspired by open source communities, the model of remixing and sharing reminds me a lot of what the Scratch community does. I think this aspect is a large motivator for students to keep on going, and is one reason I have often turned to Scratch over other choices.
Promise of more CS-centric lessons. Most of the current content is basic programming, but the team is intending to expand into more computer science specific territory over time. I suppose it remains to be seen how well they do this, but my fingers are crossed.
So, we'll see how well all this works when I actually get down and try the lessons. In the meantime, I can't help but think that designing the content would be a dream job for me. Maybe one day I'll have an opportunity to work on something like this.