We love our membership. But we shop on Amazon regularly. We are big into researching prices and often (not always) Amazon is the best deal. Getting packages in a day or two is a big selling point for us. We shop for seemingly everything under the sun...this week we are expecting my daughter's birthday present, some golf supplies and a pool part.
My husband has a Kindle, so he enjoys the ability to check out a book a month and watch movies on his e-reader.
And we don't have cable, so sometimes we use the free movies they offer. Their system is not as well organized as netflix, but occasionally we find something on there that's not available on Netflix and we take advantage of that as well.
You are also permitted to share your membership with members of your family (doesn't have to be the same address). If I remember correctly, you can share with four people. So we have added our parents and my BIL. My BIL enjoys the benefits so much, that he has split the cost with us two years in a row now.