I love ecto as well. I love pure SQL and interfacing closer to raw data. Phoenix/Ecto is where I'd gravitate starting a new project (we used it in production at our startup) for many reasons including the simplicity of deployments.
For people getting started with engineering, AR is a nice wrapping/mapping of SQL => object oriented models. There's a mix of productivity, approachability, and feature set that puts AR ahead, for me, as a general use ORM.
I would agree, though, with a strong and experienced engineering team Ecto and Elixir are quite nice.