I recently dived into Lightning and the Aura framework and I'm really wondering why you would choose Aura over any other framework. Of course in Salesforce you have no choice but what about the outside world?
The only reason I can think of is to use SLDS and Aura to create the same "Salesforce experience" outside of Salesforce. But if that's the only reason for using Aura I'm not quite sure that it will gain much widespread use.
And for a JavaScript framework it feels way to clunky and declarative rather then being just JavaScript.
Also: Is anybody besides Salesforce using Aura?