I'm not a fan of Udacity, mainly because I paid them $800 for a single course (the first in the self-driving car series) and then they blocked all my access to the course content because I didn't finish the projects in the allotted time. I was hoping to finish later because my work schedule changed, but they were completely inflexible. I should have read the fine print. The course content was OK, but I don't think they have great policies.