I haven't used it for years and I have never looked back! Even in extremely large systems, manually writing a mapping layer is quick (although admittedly obnoxious) and has helped me identify issues so much easier.
It's been many years since I was a (.NET) developer and therefore since I used automapper. Are there any VS plugins that take the tedium out of this mapping? Right click on a class, choose a class to map it to, and it creates the boilerplate code for the mapping layer?