Honestly, FireTV isn't that bad and relatively speaking, Apple TV is not that much of a break through. I seriously doubt that Amazon will release their App on the Apple TV, they've just recently refuse to sell Apple TV on Amazon, so I don't think they are about to make an App for the Apple TV. They are basically doing whatever to stop people form buying the Apple TV.
Actually it's the other way around. Amazon stopped selling Apple TV and because Apple wouldn't put Amazon Prime on the Apple TV roster. With the tvos app store, this might change. I would be surprised if Apple didn't approve an app from Amazon Prime and SlingPlayer just to be petty.