I have no experience with Jing Gong AEGs but Chinese clones are on the rise and their quality is getting so much better than before, I wouldn't be surprised if it works perfectly. And as far as Tasco scopes go, they are a little bland, not too many cool knick knacks since they aren't intended to be military replicas, but they work very well, with a clean, crisp sight picture.
I have ordered from UnCompany numerous times. I order mostly internal/external parts from them but I have ordered a complete gun before (KSC M93r). They have never messed up any of my orders and I would recommended them. However, their ordering system is a little slow, first you put in the order, then after a day or two they contact you back with a final quote price, after you send the payment you will recieve another email saying they recieved your payment, and then after that you recieve an email saying they sent your order. On average I'd say from the date I place the order to the day I recieve it is about 9-10 days. Overall, UnCompany is very good and they do not make mistakes. I recommend Redwolf over them though, A+++ for Redwolf.