Our materials are only available in PDF format. I haven't experienced any issues with accessing the materials on my iPad and cannot recall other members having an issue like this. Materials in PDF format are generally accessible on any device. Are you not able to download or view them on your iPad or you are just saying that you prefer other options? Of course, we would like to help troubleshoot if you are not able to view them at all.
I am able to see the PDFs on iPad but as I said they are not very conducive on an smaller iPad. Also I wanted some way of annotating one one device and be able to see on another. Epub would allow that flexibility.