Prime membership has worked out well for us. We order a lot of things from Amazon that we would otherwise have to travel to town to get and so we save on gas and time. And because we don't go to town that often, we get the items faster through Amazon than we would when we stack enough errands up to merit a trip to town. So, for us it is very convenient, but I agree the shipping is not quite as prompt as it used to be - I think they started saying that the "two day" shipping guarantee ran from when it was shipped not when it was ordered. We are not usually in a rush to get most things so that is not an issue - but the free shipping is important. Given how much we order we easily save the membership cost due to the free shipping.
And, with Prime you get Prime video - and even though I don't watch a lot of TV, we probably access 3-4 movies a month from that app. I think you can also get some music free - but I have not looked into that.