This is a wonderful way for students to explore Mathematics.
I work with math teachers district wide and I have used this product in the classroom setting to explore geometry concepts. It is a great visual for students to explore geometry based concepts without have to draw out multiple examples over and over to see how geometric theorems work. It will take some getting used to, and can be a little glitch, but overall it is a good product and free alternative to Geometer's SketchPad.
How I Use It
One of the biggest improvements is that now supports html 5 standards and is no longer java based per se. Which now means it runs on iPads. I posted a link to two different GeoGebra activities and a worksheet that can be found here that asked students questions based on rotations.
They also have a whole exchange system where you can find dozens of other activities as well on whatever topic you may be teaching.