Nice to hear, we are thinking about adding image export and also markdown export. We are awaiting more feedback regarding those two and based on that we will move forward. Thanks for your comment.
OK understood, for the moment we get only the main content, we are working on a new "parser"that can fetch the main content and comment attached to it. For this you are right we don't extract content but we expect to have this released soon. For the book you are right, we will think about it and how to integrate it. Thanks for the feedback, this is greatly appreciated.
We tried several stackexchange url and it did work, for example : http://codegolf.stackexchange.com/questions/92138/the-letter... which has a complicated layout, generate an epub or anything else and you will see the quality is good, we agree that the pdf renderer is not as good as the other yet but we are working on it. If you pls send us at hn at documentcyborg.com or via comment here on hn the link that didn't work so we can get better that would be great. For the book idea the problem is when to stop, if you make a book out of amazon it will take years. Maybe the possibility to add several url and from that generate a "book" document. Thanks for trying the apps, we just wished it was up to your standard but we are constantly improving it since 3 day ago when we launched, so hopefully we will get there soon.
The layout for doc,odt,epub,rtf,txt is as good as the medium article, for the pdf you are right, we are fixing our pdf renderer to not overflow element right now. Will keep you updated once done.
We don't just convert to other format we try to extract the meaningful content only and not the whole page. Thank you very much for your positive comment.