Well talking about snapdeal it has only big brand ambassador and nothing else. There are some good deals on the products but their services are very poor when compared with flipkart especially.as you can easily get experience by purchasing products from both sites and also at the time of returning the product you surely face difficulty in snapdeal on the other hand it's easy to return any product in flipkart.
I always purchase all stuffs from flipkart but last time I made a mistake ie shopped from snapdeal
