I have shopped two high value products from FlipKart and both were from WS Retail . One was a 42 inch TV and the other was an automatic washing machine.
I purchased the LED TV during the big bullion day sale and the washing machine on a regular day. On both occasions I have received the product with a window of 24 hrs! . A delivery this quick without even paying any express delivery charges is amazing. I have not seen a same day delivery for free even in the United States.
On comparison of the 3 major ecommerce site in India, I would rate as below on personal experience
1) FlipKart - Quickest in delivery and a good customer support
2) Amazon - Average delivery and has a online chat customer support
3) SnapDeal - Very bad delivery and an incompetent customer support.