It fails primarily, in the same place and on the same photo and on both devices (which are obviously synced together). Occasionally, the iPhone backup fails on the 31st image, while the iPad fails on the 100th image. But they usually both fail on the 86th photo (Han Solo; go figure).
Contacts and Calendar back up fine.
One feature that was greatly appreciate in the PhotoFast app was being able to zip files (everything else was garbage). Would like to see added to the SanDisk product, as some file types that I work .xml and .pem will get filtered by corp firewalls otherwise.