Evaluating apps for the South African CAPS curriculum

One of the hardest parts of choosing an app is deciding if it will assist you in achieving the skill you are trying to teach. There are various resources on the internet which will tell you if an app is aligned to the common core standards or CCS in America, but hardly anything for the South African CAPS curriculum.
And so we are often left downloading apps that do not target the skill we were hoping for (although we may be able to use this app either for foundation skills or for extended work).
Because of this I have started working on a rubric which will hopefully allow us to choose apps that are better suited to our learners and the curriculum we currently employ in our schools. However, in the meantime a good bench mark to use is that of Kathy Schrock.

She has designed a rubric called the evaluation rubric for iPod/iPad apps. This rubric is quite useful in determining how appropriate an app may be for the skill you are trying to teach and therefore allowing you to make a better decision about the app you are considering. Go have a look at it here - iPad rubric

In the meantime, I would like to ask all of you for your help in the development of this rubric and ask you to let me know what you believe should be in the rubric? For me the most important aspects of an app are:

• Does it offer differentiated learning?
• How motivating is the app?
• What is the cost and does it include any in-app purchases?
• How can I adapt or customize it to my learners needs? 
• Does it provide me with a summary of my learners at the end of their session?

For me, differentiated learning and customization are incredibly important as I teach special needs students. However, due to the varying teaching methods worldwide I feel that customization is possibly one of the more important aspects anyway. So let me know what you think? I have also included a poll so please vote...