I have been in need of a viable solution for ebook cataloging and archiving for quite some time, and I must say it is tough to beat Calibre. Granted, at times I have had grown irritated with it due to the clunky interface and some stability issues..but hey, its free--you could easily spend money on worse software (with less functionality).

In all fairness, I personally am not one to fortify the idea that poorly written,useless applications can be pardoned just because of their "free" status, but I think there really is a noteworthy piece of software here which has a nice array of both sophisticated and practical functions...lots of potential to build on as well. Speaking of which, it seems like I'm always prompted to update the software when I launch it. From what I gather, the dev is actively working in the background to refine the app--much appreciated!

cross-platform=awesome

If anything (and I do apologize if these features exist and I've missed them), perhaps allow for the addition of custom fields in column view. i.e sortable fields like: formats, notes, categories..etc. Also, maybe a minimal, space-saver *alternate* theme or something would helpful--> Macbook screen is small :/