I purchased a phone for my son that became defective within 7 months. Amazon wanted to only give me a partial refund. My state has an implied warranty law, the Attorney General did a tv segment stating that no need for extended warranty, and if companies don't honor the state warranty, they are in non-compliance. It took me a while and also had to provide the law and they finally refunded the full amount.
For the most part I have had good luck, and not to many issues with needed to use refunds or replacement.
I have noticed of late the prices on some of the products are far more expensive than many brick and mortar stores, so check prices before you buy on Amazon. I still check reviews out of products I am interested in. The problem today is now they have people who get free items to review them, makes me wonder how legit the review is.