I used to buy the products from Gleim. When I trained for the FAA Instrument Rating I had the test prep software on my notebook because the best time to train for the exam is while traveling (long distance flights, nights at the hotel) Recently I switched to Apple Mac Book and also own an IPad. Since my next goal is the FAA CPL I was about to buy the Gleim test prep again for that test, but apparently Gleim did not see the importance to serve Apple users. On their site I expressingly says the test prep only works with Windows PC. I also could not find an App for the IPad from Gleim (may be there is one at Itunes US but I am from Germany so I only could search in the german Itunes store).
Instead I found this Aviaton Exam App for my IPad software. So far am impressed how good it works. The explanations for each questions are short, comprehensive and written with a certain sense of humor. The App is very easy to use. The price 8,99 Euros for the questions during 2 month time is not exaggerated, and even if you need them 4 months it is still a great deal compared to Gleim, and I hope for that money we are getting updated questions. But so far I am very satisfied.