Your first question to yourself should be, Why not just get the JG AUG military?
There is a 40$ price difference here, and all your getting with the Echo 1 is a prettier box. And as Booligan has highlighted before, there is the ever looming chance that you will just get a JG gun in an Echo 1 box, or an Echo 1 in a JG box.
My friend got a Echo 1 G36c, when he bought a JG G36c. He saved 25$
I would suggest that you give it some thought before spending more to get the Echo 1. Considering it is priced at about the same price as the G&G nylon fiber series.