I want to buy new  quadcopter from RC Mumbai. It is good and faithful for that? Please suggest me..

I've bought a lot of stuff from RCMumbai in the past 2 years and they have always provided good service. They had some problems initially, but every new venture has to go through that.

I've always received my stuff within 2-4 days. They also helped with changing some products even after I had placed the order. 

Thnx Swapnil. I need one more help. I have RCB6i Tx having potentiomete issue. RCBazaar asking Tx for repair but it's in my native place. You can where i can get potentiomete in spare?

You should repair it from rcbazaar only. You will have no problem. If there is any other problem they will diagnose it too.

Even I got my few equipments including Naza system etc from RC Mumbai. Had some billing issues initially but its ok ..they have good range of products in mumbai. I could recommend buying from them

Go ahead and buy it.
They have good service