The customer service is pretty amazing compared to most other stores, at least in my opinion. Returns are easy and free, and you get a replacement shipped right away but have weeks to return the item.
returns are not universally free or easy. I bought a power supply for a computer (corsair) and it went on sale a week later. I called to get a price adjustment and amazon told me they don't match even their own prices. So I said I'd return it and order a new one and I was told I'd have to pay return shipping.