In Connected Learning we've rely heavily on GoogleDrive to record students' collaborative work. What we've found problematic is the fact that GoogleDrive is often temperamental. It works, it doesn't work, or it crashes. And this all depends on the iPad being used, whether students are viewing it through the GoogleDrive app, Moodle, desktop view, mobile view etc.
A common mistake students make when initially trying to access their documents on GoogleDrive is by attempting to log into GoogleDrive directly rather than going through Moodle. Another problem is when students are logged onto GoogleDrive but can't see or access any shared documents. I've found that changing the view settings (either found at the top of the page or at the very bottom) from Mobile to Desktop more often than not solves this issue. However, our ultimate backup plan has been to access GoogleDrive using laptops. Fortunately, fewer and fewer students have had to resort to this.