Very nice looking and what it does do, it does very well and is very easy to use. However, there are a few criticisms I have of the app after a brief test run:

1. Localisation is due to come, but it is a shame it isn't here in the 1.0 release. FWIW, while all the arrows point to the US amazon website, when you add a new item, it actually pulls down the UK amazon website info (I am UK based) which is a bonus considering that I don't think it is meant to as of yet.

2. It's a shame that you can't point it at other websites for more pertinent info (e.g. IMDB for the film info and reviews)

3. It's a little sluggish interface wise.

4. I can't find a way to add several items for one "creator" at one go - i.e. if I want to add a number of albums or books from the same artist, I have to do it separately for each album/book as there doesn't seem to be a way of adding many at one go. This will make it a bit of a chore setting up your initial library. Ideally, it should also pull the info from your iTunes library into Delicious Library - something for a future release.

5. You should be able to add some more default collections such as "Comics" etc. and you should be able to group sub-collections under the appropriate top level (e.g. Books should be divisible into Novels, Manuals, TextBooks, Catalogues, etc)

6. It is crying out for a Keyword/"Smart Collection" feature akin to the Smart Albums in iPhoto so that you can have new additions auto-sorted into your pre-defined Smart Collections.

7. The Help section is quite flimsy and online at the Delicious Monster website which isn't particularly good.

With that said, it would make a great addition to the bundled apps on new Macs and I suspect future versions will resolve many of these issues.