To add to what Mark said; the problem is getting files off an iPad into, say, a PC. Whether comics, or documents, pictures, Keynotes, etc, Apple does not make it extraordinarily easy to get material from its products to PC directly. My school system uses iPads 1:1 with students but the whole district operates on Dell computers. We have to use a third interface to get the machines talking. Extra steps, but it works fine.
I have, I don't know, maybe a terabyte of comics and pulps. I wouldn't recommend using an iPad, or any reading device for that matter, as a primary downloading tool. I've never understood storing anything long-term on an iPad. I view those as reading devices, so I load, read, and delete. Therefore, if a reader app lets you read a comic, it's pretty much done its job.
Although we all have our own ways of doing things. Once I read a comic, I usually don't go back to look at it for ten years or more (most of the time much more)