I sent this link to Chris Harrow, a colleague who teaches math at The Westminster School in Atlanta. Here are his first impressions:
Cool = very smooth functionality on the iPad, you can do all the explorations in the most excellent iPad touchscreen environment, a very tactile approach to learning geometry.
Frustrating = you have to create the docs elsewhere, on first exploration, I don’t see a way to do constructions directly in this app. If a kid gets a good idea that requires additional “stuff” on the construction, s/he may not be able to instantly follow up on intuition.
Any one else want to weigh in?