One can’t quite understand there isn’t an iOS app parallel to Mac OS X’s Preview. In the current state of things, in order to have PDF documents available on desktop and mobile devices, one has to use a folder from any iOS application intended to manage PDFs.
And such apps are a bunch. Personally, I own PDFpen 2 and GoodReader. Another app well recognised is PDF Expert 5, by Readdle. Allegedly, the lack of a PDF viewer from Apple opens the door to third party actors and allows them to work whitout the competition of the mother company. However, there we have the e-mail and the browser apps. I use iCab Mobile more and more as a Safari alternative, either in the iPad or the iPhone, and that doesn’t mean Safari shouldn’t exist. As for e-mail, I haven’t tried anything different from the Apple’s own yet, but I could and many have done it.
So then, what’s the matter? Isn’t dealing with PDFs a service of the same rank than e-mail and web browsing? What I said in the title: a mystery.