Took this for a trial run. Overall, I like the look and feel of this (despite some UI quirks and some awkward uses of English), but not sure I really need the app (although: it is nice to have the option to access docs in iCloud in your iDocument). I'm pretty good in keeping things organized in hierarchical folders. Couple things I noticed with this app:
* Performance: can rev up your CPU during indexing large folders (on my MBP 17" 2011 with 16GB RAM)
* Organization: the view area will list things alphabetically; in thumbnail view, each alphabetical category (#, 1, ..., a, b, ...) will open in expanded view; no command to collapse the view for easier scrolling to target a particular section.
* Footprint: you can throw all kinds of stuff into this app, but if you decide to remove content, there is no "garbage collection." Everything you add to the Library, will remain indexed in the Library > Thumbnails folder even AFTER you remove items from the Library. This can be an issue for space-conscious users (or users who want to store their Library in the cloud).
For example, I added a folder of some 30,000 images and documents to another folder I already had in iDocuments. The size of the Library increased from 2.5 GB to some 20 GB. Even after I removed the newly added folder and then restarted iDocuments, the Library folder remained at 20 GB; nothing got removed from the Thumbnails folder. No option to rebuild the Library/DB and remove irrelevant content. (The makers of the *pedia apps, Bruji, for example, give you the feature to Option-click Help and there you get all kinds of options to remove invalid or outdated data, including removing covers from items no longer in your *pedia database.)
Other than that, looks like a good (albeit somewhat basic) option for users with a penchant for throwing things into a bucket and tagging.