Let me introduce you to BookFusion. BookFusion allows you to easily organize your eBooks regardless of format(PDF, MOBI,EPUB,DOC,TXT, FB2, CBZ and others) while allowing you to easily read on your desktop(Web), Android and iOS devices.

You are able to easily send books to your Kindle from the same app using our Send To Kindle feature.

More details at https://www.bookfusion.com/reading/cloud-library

PS: I am the founder of BookFusion and would appreciate any feedback that you might have.