The program is awesome.. only a few features are missing like panning with the keyboard and slightly better sort options for the pages.
I read Mangas in it and the program does a really great job! It feels good you can edit alot of additional Information about the Book or Manga and the program even recognizes when you move the Book / Mange into another Finder Folder like iTunes does!
I have absolutely no problems with adding the Mangas since the program seems to support a lot of different ways to do.

I think there is a good chance the missing features are going to be added. And if you have any other suggestions you really should let the developer know and write a suggestion on their support page.

Although some much-needed features are missing at present, I have my eye set on Ehon becoming the de facto standard for comic and manga management on the Mac. The user interface is headed in the right direction and needs just a bit of polish -- especially for those of us who favor our keyboards, not mice. Entering data is tedious if one attempts to use the Tab and arrow keys to move between fields; it seems clear that the developer intended users to take their hands off the keyboard and put them on their mice to move the cursor a mere 10 pixels and click, then repeat every 10 seconds. This is the largest problem with Ehon (this and tag entry), and it must be fixed.

Instead of nitpicking on the other problems, though, I will say that I finally found a desktop app that rivals the best of the iPad apps I have been using. For those who read mobile manga, you know that most iOS manga apps are so-so, but a couple are very good. This app is very good other than the polishing and added features it is.

To the developer: I would be happy to give you more feedback if you let me know you're interested.

If you're looking for a way to catalogue your ebooks this is a really nice choice. I've tested it with quite a few formats in my collection and so far Ehon has handled them all without a hiccup. It inserts as much information from the file as it is able to and allows you to edit All the information. It has integrated readers for the formats as well, so you can read right with in the application. Finally it has a really attractive interface. It really does look good and keeps within the 'Mac' look and feel. It is quite quick in its imports and does a good job as far as I can see. There are other apps that can do this, and may have even more options, but they're slower and more complex (and not as good looking!). For my needs, Ehon fits the bill very nicely.