Excellent physics playground with sandbox and lesson-driven capabilities.
Honestly, I wish I was a teacher so that I COULD use this with students. The interface has a bit of a learning curve, as there are combinations of navigation menu items and right-click context menu items that are not immediately obvious. However, the interface is no more complicated than Microsoft Word or some video game menus, so it wouldn't be any great obstacle. The only downside is that it is 2-D, as 3-D modeling would open up new ways of interacting with the scenes. However, the concepts taught are spot on.
How I Use It
While I do not teach a class, I downloaded the program and played with it for a while. I intend on using it with my daughter when she takes physics, and recommending it to my friends. The pre-generated lessons are fantastic, and being able to create and share your own scenes would greatly enhanced collaborative learning.