I uses amazon for my most of the online purchase. It is the best online service provider in industry.
Website and App both are best in look and feel, speed and user friendliness. Sometimes you will get offers on app purchase which is great.
They provides quality products. Most of their products are quality assured by them. You can see assured tag in front of products which are quality assured by Amazon.
They have both immediate delivery and normal delivery options available for all products. If you need imediate delivery you need to pay some extra amount which will deliver product in 24 hrs. If you are premium customer of Amazon you will get all delivery in 24 hours.
They have decent customer support. They will answer your all queries immediate, Only thing they need to work on is refunding time its about 7-8 days.
Because their live order tracking system it is reliable to track your order and manage your order time.