I've been thinking about this particular topic for a while in finding what could possibly be the worst streaming app that I've had to deal with recently.
For my experience I have to place the Amazon Prime Video app on the Apple TV to be one of the worst apps I've had to use. The slow loading of the main menu is just the beginning. Moving from each selection brings about a very noticeable bit of lag that makes you overshoot or even undershoot where you are wanting to select.
Then comes the next major pain point is when returning to a series you had been watching, you're brought into the first episode of the first season, ugh. Have to scroll down twice, select the season drop down, scroll down some more for the correct season, and then go to the next episode you were wanting to watch.
Want to restart an episode, then good luck trying to highlight the episode in order to select the restart button. I haven't been able to successfully do this without starting the episode where ever had left it, pause it or bring up the playhead in order to select the restart button.
Mix all of these great user experiences together and you can also have the experience of the app constantly just not working at all. Want to watch a different series, cool, back out of the currently playing episode and you're presented with a blank screen with only the three menu options on the left side. Press back on the remote, nothing happens, over and over again. Great, let's force close the app and try again, but wait, the app doesn't fully load, force quit it again and maybe the next time it might work.
For a multi-trillion dollar valued company, Amazon hasn't even tried to scrape the bottom of the barrel in providing an app that works.
J