I used Jep Flite Pro leading up to my IR. Found it very usefull, it helped me become familiar with the prcedures and plates that I was likely to fly during the test. Also, it helped me increase my multi tasking capacity and my ability to look at the 'big picture'. As for using it at PPL level, good fun hooning around the skies trying to do barrel rolls on the ILS and such. Personally I think it would have led me to concentrate too much on the instruments and not fly visually.