After installing the BizTalk Adapter Pack, we can see it listed in the programs list and bindings get listed when we choose WCF-Custom adapter type. But I recently realized that, we need to manually add each adapter of Adapter pack in order use directly instead of WCF-Custom adapter with respective binding type. Steef has explained these steps in detail nicely in this blog post. Although we could technically use both WCF-Custom and explicit WCF adapter, properties in the Configuration wizard of explicit WCF adapter provides more relevant properties for respective receive location or send port. One of the observations I had was, send port of WCF-Custom->sqlBinding type shows polling properties which are applicable only for receive location and these are not shown if we use WCF-SQL adapter and also we get neat categorized view of properties with this. If there are any other major differences between WCF-Custom and explicit WCF adapter, please feel free to mention as comment to this post.
Also remember that, name of the adapter is not updatable once it is added and the work around to do this is to delete the adapter and add it again.