I’ve used Amazon consistently for over 2 years now and have not been back to Flipkart and the others at all in this duration.
Their customer support is quick and helpful. I’ve had most queries resolved within the same day itself. The only negative in this would be that on email tickets, you’re assigned a new support team representative each time you reply to the thread. So if one person could not resolve your problem, you often have to state the same problem again and again from the very beginning.
Products more often than not live up to their description.
Delivery times are usually quick(quicker than stated, very often).
Overall, a good experience.