I'm relatively new to .NET (though an experienced developer) and it took a couple of hours tops to research and write my first .NET CRUD app. It took even less time to begin writing useful cross-platform tools. That said, .NET Core still has some warts, and I look forward to it maturing throughout the year. From my perspective, it looks as if the development team moves pretty quickly.
I think this is great collection of resources to help onboard an engineer new to working with .NET and understanding the landscape.