The best part about Review Assistant is that it is integrated into the Visual Studio and TFS.
What do you dislike?
Somewhat pricey if all you are looking for is a diff tool. There are a number of freeware tools to review code that do not provide the integration with MS tools, but that integration may not be worth the cost.
What business problems are you solving with the product? What benefits have you realized?
* We monitor all Review Assistant reviews to prevent fraudulent reviews and keep review quality high. We do not post reviews by company employees or direct competitors. Validated reviews require the user to submit a screenshot of the product containing their user ID, in order to verify a user is an actual user of the product.