I like that the item is prominently featured in "A". It's clear at a glance that the primary content column is devoted to information about the item, and the sidebar contains information about the collection holding the item and related items.

From a researching perspective, the reactions and comments would be useful but not so much that it should be more prominent than the collection data on the item itself.

The header design in "A" is also nice. With a clear flow of logic from "Duke" to "Digital Library Collections" to "Browsing".

The only thing I'd really change is an actual search box for the current collection instead of a link to "search the current collection".

It would also be nice if the various pieces of metadata below the item were links to searches for those terms.