There is always the confusion of which video is free and belongs to Amazon prime (free) and which ones need to be purchased. Compare that to netflix - You see it, its yours to watch.
Amazon originals are a torture chamber, I cant even name one. Compare that to Netflix - I renewed my membership just to watch House of Cards.
Amazon, Google, Facebook they all fall into this same problem of having a consistent UI across all their offerings. This constraint of consistency leads to a UI design which might not be the best for that particular product. Netflix because it offers just one thing, video streaming, can design UI best for discovery and personalization and wins compared to Amazon video any given day.