From my experience with iOS, it is much inferior to android in system feature. Its logic of doing things is not for your convenience, but for your its safety; and for this odd purpose, you cannot do many things that is so natural on other platforms that it shouldn't be deemed as a "feature", such as transfer files with other devices, save a document and open in another app, etc.
As I read, iOS has a unique sandbox structure, which means every app is isolated, that an app can only access data of its own, which suggests data sharing is not possible, or complicated. There are shared documents directory but I never know how exactly it works, and it seems rather limited. It seems only iTunes has special privilege to manage data. Other tools calling iTunes lib are more user friendly, like iTools. If you need a true file manager, you must jailbreak it. But even after that, you still cannot do simple tasks say open a html file in your device with Safari, because Safari app locked in "sandbox" just can't access that file. Typical things iOS can do is processing data from network, and back to network, and do it only in one app. That makes iOS a specialized toy.