Don’t waste your time if you really want to study.

Have been “using” this software since 2011. First with Mac version later on iOS, too. Meanwhile, I looked around for other tools and must admit I staid with Mental Case in lack of a better tool. But its time to say good bye and move on.
Yes the interface looks sort of nice (overdisigned IMHO), but its buggy and iCloud synchronizing is damn slow and unreliable at best. Better backup regularily or you are at risk of loosing your data completely (happend at least twice to me). If you look for a reliable tool for sincere study work, do yourself a favour and buy a stack of good old paper cards and do it the old way. You will save a lot of time and effort for your learning task.

Vossilius about Mental Case 2 — Flashcards for the Serious Student, v2.6.5