BusyToDo is a simple yet powerful To Do app for iOS. It is compatible with the Reminders app and syncs with iCloud, Exchange and other CalDAV servers. It works particularly well for syncing tasks with BusyCal on Mac OS X.
Unlike the Reminders app which provides no means of sorting or filtering your tasks, BusyToDo lets you sort and filter tasks by due date, priority, or calendar. What's more, alarms in BusyToDo are optional, so you can schedule tasks for a specific due date without having to set an alarm.
If you manage tasks in BusyCal, BusyToDo is the ideal mobile companion.