Unlike a lot of other seller-buyer service provider Amazon does a pretty good job.
You can check various seller selling the same product at different price with different delivery charges and terms, which make its easy for you to choose from.
It kind of does the comparison with all the sellers, provides the rating of the sellers which kind of builds the trust factor. Reviews are given for most of the products.
Delivery is fast. Never experienced any flaw in my shopping experience with Amazon. Mostly purchase Electronic items from Amazon.I have shopped on both the website and the mobile app. It works just fine.