Well the cheapest is Roku. You can do some interesting things with the Nvidia shield. I have nothing to add about the apple product, im not familiar with it.
Roku 4
General Roku reviews in the last year are likely outdated. That's mainly because they waited excessively long to update from Roku 3 to 4. The Roku 4 can do 4k, and streams pretty much everything from my NAS or provider.
I just pulled the trigger on the Nvidia box. It is bundled with the gamepad, and free ($43 value) remote. I'll report back after I get to play with it.
I use my WiiU to stream everything and it works really well.
In the settings mode for the browser you need to set the user agent to 'ipad' and then it'll be able to stream hd movies/tv from 1channel, kissanime/cartoon, youtube live streams for sports, etc..
Wii U for Netflix and Amazon, and a cheap laptop with HDMI out for the rest (Kodi with addons for movies and sports, mostly).
The only downside I've seen from cutting the cord is when it comes to sports. For most sports, you have to watch it live if there's not a replay somewhere.
Welcome to the club. Cut the cord for about over a year now and glad I did. I bought an amazon firestick that had kodi preloaded and that's what we use on our tv in our living room.