OzCode provides many additional features during debugging sessions over the standard experience within Visual Studio. The features that assist me the most are the ability to search in collections when hovering over a variable (e.g. look for customer 123 in the collection) and the ability to see the anticipated values of variables or statements beyond the currently executing line (e.g. Oz-Code evaluates the upcoming code within the block and displays what the results will be, including if an error will be occurring). Review collected by and hosted on G2.com.
There isn't really a downside from using OzCode other than the purchase price, which is minimal in comparison to the productivity gained from using the product. There is some slight lag in Visual Studio start-up because of the extension being loaded but it's only a second or two. Review collected by and hosted on G2.com.