Last night my brother gave me his comments on XNA after having tried to use it for a full day. The API and usability are very good, but the experience is bitterly let down by the documentation at this stage. The examples contain errors that, OK, I can fix but only because I know enough about how DirectX works in the first place in order to make the fixes but if you don't then you're pretty much stuffed. The rest of the documentation is unfinished and missing pages and methods which makes exploring the API hard if you don't have...