Re: We've made prime delivery faster.
I worked out many years ago - in the days before Prime - that buying from Amazon Marketplace Sellers was a bit of a mixed bag. Since then, I avoid them. I will consider buying "supplied by x, fulfiled by Amazon", but other than that will go out of my way to make sure I'm buying direct from Amazon rather than a third-party.
Occasionally you find a third party that's ok, and then you realise that some of them actually have their own web shops, and it's often quicker, easier and cheaper to buy direct.
As for address mix ups, it's not just Amazon, it's any delivery that relies on somebody with a postcode and a GPS unit. One day we will just accept that pizza or Indian or Chinese delivery, because it's all paid for online and it is becoming tedious to keep redirecting the delivery driver - the house in the next street (which doesn't actually have the same postcode but does have a very similar street name) seem to average about one takeaway a week, at least a half of which come to us instead of them.