I have both the IPhone app version and the Kindle version. The iPhone app has far superior graphics and style. Finding a particular book, chapter, or verse is much quicker, but it lacks landscape mode that kindle version has, which is a drag. Also, the iPhone app version does not include cross references in the commentary, which the kindle version has. I find this very useful. Finally, the kindle version includes a cross, which, when pressed takes you directly to that verses commentary. On the iPhone app, you have to scroll until you find the corresponding commentary.
Maximos7 about Orthodox Study Bible