I just think it is the best and easiest online shopping experience out there! Best and easiest because of the wide range of products, great customer service - always available and I never had to wait in line, easy returns, good recommendations, quick deliveries ( they can't give you a precise time.I think this is something they were able to do when they had their own courier delivery it. but for me personally this isn't a massive issue since it's usually dropped of with a neighbour and if needs be I can choose my work address as the place I want to have the parcel delivered to.)
I also like the customer reviews, they can be really helpful and I like the fact that Amazon took action when reviews were found to be untrustworthy, they deleted the reviews made my people who had not bought the product. This shows, that they care more about keeping us a longterm satisfied customers, than making a quick buck by selling us stuff that is probably crap because the seller had to bribe the buyer for a good review!