When writing in the app I would recommend using a stylist of some sort. Initially I found it difficult to write in the app but after time, it improved. There is a feature in the app which allows you set wrist protection and position. This is mention to take account of you hand resting on the screen while writing but I found it patchy. Sketching and drawing on the app was excellent, different line weights and colours are available and detailed design sketches can be quickly produced.
Overall an app well worth it money and a definite for any teacher using their iPad in class.