The OOTB experience for code reviews isn’t horrible (shelvesets work fine, in my experience), but there’s not a good built-in way of tracking the code review process, especially the feedback given.
The "TeamReview by Example" on the project’s main page does a great job getting across what a typical code review is like with TeamReview, and if you’re doing code reviews (you should!) with TFS, this sure looks like a great way to go. It’s on my TODO list to try it out myself once the current queue of work gets flushed. 🙂