Collaborator vs. TFS code reviews

I've been using SmartBear Software's Collaborator (formerly Code Collaborator) at work for some time now.  I looked for any info out there on how it compares to TFS code reviews, which happen in Visual Studio.  I couldn't find any, so here is my first shot at a comparison:

Collaborator possible advantages

• Can add updates to a code review after it has started (as well as any other new files as desired) 
• Real-time chat/updates 
• Takes place in a separate tool to provide a different mental context for reviews; does not affect changesets, code, etc. directly
• Allows for over-under diff view and many other view configuration
• Allows for flexible workflow - imposes a minimum amount of process 
• Can create reviews from arbitrary files (not limited to version-controlled files) 
• Can be used by users that don't have TFS or don't want to open Visual Studio 
• More full-featured in general (small features too numerous to list) 
• In active development (Microsoft isn't often adding features to TFS Code Review)

 TFS Code Review possible advantages

• Takes place in the same tool as development (Visual Studio)
• Automatically creates TFS work items 
• Insists on one certain workflow for doing code reviews 
• Can create reviews from TFS: pending changes, changesets, or shelvesets 

The bolded item is particularly compelling, in my opinion. What other advantages to either can you see?