My Take
It is a fantastic way to learn and engage students in the three areas of science which they address, but it is only those three very narrow science concepts. For the money that you have to spend they should definitely have way more content. It seems more like a free version that they try to get you to upgrade from, but yet it is not. It would also be nice to draw and label within the app instead of drawing a picture and than taking a photo of it and labeling in the app. Although clever, it can just as easily done in one of the many free whiteboard like apps out there. The same could be said about the videos. It would be just as easy to use a video online and than have the students use an app like Explain Everything (way more worth the $2.99 you will spend) to show their understanding.
I would recommend this app only if they were to update it every once in a while with new content, which they haven't done as of yet. So save your money and skip this app!
How I Use It
This is a very nice app if you need to support, extend or just introduce the concepts of Layers of the Earth, Liquid, Solids and Gas or Adaptations and Evolution, but that is it. Students enjoyed the video lessons and the activities, but finished very fast with not much extension afterward. It makes nice use of students creative ability by having them draw (like the earth's layers) and than take a picture and label it after it uploads. Students did complain that they would rather draw within the application instead of on paper than taking a picture, and that there should be more content.