And their Two Day Delivery Gaurantee is increasingly neither two days nor a guarantee.
1. http://time.com/money/3955429/amazon-prime-late-deliveries/
The last few times I've bothered to complain I've been offered a $5 credit instead.
I live too far outside London to use Prime Same Day and Prime Now options. (I.e same day and 2 hours delivery). I would be interested in how often they meet those much tighter delivery times?