There is no point in reviewing the phone itself since anyone who is actually interested in buying an iPhone would have read its reviews on the more relevant websites.
I can talk about my experience of buying iPhone from amazon. The product is 100% original, its Indian iPhone model so don’t be concerned about claiming the warranty should you need it.
Some negatives:
1)Even after paying for same day delivery I got my phone after one day
2)Packaging of parcel was not so great(less bubble wrap) eventually damaging my iPhone box corners(apple enthusiasts love the product’s box also, trust me)
3)I bought it in march end but the phone manufacturing date is Dec-2016, making it 3 months old, this effects the battery to a minor level.
Also you have to ensure that the warranty starts when you actually bought the product and not when the product was manufactured, with non-original product this is the first risk.