The plus-point in Amazon is its variety. Its got so many options which you can have a look. The web-site is not as decorative and good-looking as Flipkart. It also lags behind in Electronics departments.
And yes, it does not allow COD on all pin-codes, I live in Rampastha Colony, Ghaziabad just 300m. away from Delhi but COD not available. What will happen in other parts of UP. This is a big problem. It has brought Amazon Prime with 1 or 2 day delivery guaranteed. Overall, all I can say is I like Flipkart more than Amazon.