In my experience, people's reactions to the XTutor have been hit or miss. Some people despise it, while others (me included) love it!

I taught an abbreviated version of 6.001 in China many summers ago, and it was sponsored by Microsoft's iCampus project to test out different learning tools. XTutor was one tool we used, and while it certainly helps the student in that it gives immediate feedback, what was surprising to me was how much it helped us, the somewhat inexperienced teachers. Teaching the 6.001 course would have been much more difficult without it.

Lots of people have knowledge they'd be happy to share. The easier we can make it for them to connect with learners, the better.