GitHub User: verticonaut
Thanks for giving some samples to the recent Tweet-Stream about this topic.
Concerns let you group functionality - nice. But in the end it all ends up mixed into the consumers class (User). I know it's nice Ruby magic - and there might be reasons or use cases to use Concerns. But somehow I like the service approach more. It's more explicit, better testable and more OO style - less 'Ruby meta style'.