It's nicer to control on the Apple TV than FireStick. Way nicer experience with other apps. FireStick is too confusing to find your apps. Obviously they want you to use Alexa.
I haven't watched enough on the others but Apple TV. Sometimes you'll run into Apple TV bugs that never get fixed. Sometimes the sound will randomly go out and you have to restart the Apple TV. Happens to me on my Apple TV 4K and happens to my parents on their Apple TV 4 1080p. On the DirecTV end, the picture will randomly go black and you have to flip a channel and flip back. These things happen maybe once a week.
I haven't watched enough on the others but Apple TV. Sometimes you'll run into Apple TV bugs that never get fixed. Sometimes the sound will randomly go out and you have to restart the Apple TV. Happens to me on my Apple TV 4K and happens to my parents on their Apple TV 4 1080p. On the DirecTV end, the picture will randomly go black and you have to flip a channel and flip back. These things happen maybe once a week.