Well... it depends on the type of product you need... the customer service provided... the delivery pace...
If you are looking for groceries, cookies and chocolates then there is this site
*www.storrz.com which gives a gr8 service... Once i had bought a different kind of atta and realised it only after opening it up.... I just called up their customer care and they offered me a replacement...
Seriously i was shocked... never expected a replacement for a used product.... But the only negative aspect is that tey dont deliver groceries outside india...