It was good until iOS 7

Other than mismatches between ghamari & shamsi event dates, the app started to crash when tapping on convert dates tab (tabdil tarikh) after the new iOS 7 was released.
The app has not been updated since Jan 2012, so seems like it is abandoned. Time to switch to a new app for me.

Yamessy about Taghvim Pro, v2.61