I have Prime and have had it for the past several years. On the one hand, I really haven't put detailed thought to see if it is actually worth it for me. On the other hand, I would say from a practical point of view, it is!
I also am able to share my account with my mom as it allows you to have a family member on the account. So we split the cost and make it only $50 a year which is not all that bad.
My mom I know uses it for the video more but since they were not able to get streaming when they lived overseas, (because those countries pirate movies) by being under my account they were able to get access.
The two day shipping has been a life saver for me. Also, the one day discounted shipping has come in useful from time to time.
One notable time it came in handy was when I proposed to my wife. I went to Illinois to ask her parents permission to marry her and I wasn't sure the exact date I would be proposing or if they would tell me to wait.
They gave their blessing so I had to scramble to make preparations for it.
I ended up proposing in a gazebo at a park in MO where we were visiting my parents.
Thanks to Amazon Prime, I was able to get supplies such as lights, candles and rose petals within a day of ordering them and just in time for the planned proposal.
From time to time I also have friends who want to get something quick but don't have Prime. They have asked me to order it for them and given me a couple bucks for my trouble.
So all in all, I would say it has been worth it for me!