The reason I chose screencasts is because usually people make it with a lot more detail or just do it from scratch and see everything you need to do to start running the plugin, the code, and everything because they record their screen and explain everything they do. But when you're reading documentations, there's a lot of people who is lazy to explain everything and miss a lot of important things and you have to do a lot of research for specific situations that should be common but find the answers on forums, blogs, etc; everywhere but the actual documentation and a lot of times what people do with their plugins is say well this plugin does a lot of things but the documentation is a mess or just simply don't explain all what it can do with reasonable detail.