Alternatives to "Shelves"

[Comicsnut]

If you're not familiar with Shelves it's an application that one can use for keeping track of collectibles such as books, movies, video games, toys etc.

As a collector I use this app quite often but it's not quite exactly what I want. For example if you have more than one of something, you can't have multiple listing of the same item - you need to enter the "quantity" for each item for which you have more than one.

Does anyone know of an alternative to Shelves?