I was a little surprised, mostly because all the talk has been of the Amazon app for the ATV4. But I am a little bit happy (got it) and a little no to much (one less reason to upgrade to ATV4K)
I still use and prefer the ATV3 (I don’t have a 4K TV). I’ve played around a lot with the ATV4, but the simplicity of the ATV3 in the UI and design is something I love. Prime on ATV3 might have just made my Fire Stick irrelevant!