Zoo2 is beyond good - I have hardly words for it!! I have been using Zoo since the first release, but Zoo2 is just a giant leap. It is so versatile, and without being a programmer, it is so easy to create and present my site in all the different ways I want it to look like. I make page types for products, galleries, articles, write-ups, FAQ, downloads, testimonials - with drag and drop.
The price is nothing, compared to the application you get, and the support yootheme gives in their forum.
I was looking at alternative CCK's a while ago, but now there is nothing that matches Zoo2.