Fire TV box has more power, 4K support (no content and you need a 4K telly), expandable storage, Ethernet socket, supports “high performance games” (whatever that means. It’s Android so it’s phone optimized games at best I guess).
£80 though. Was £60 in the recent sale. Almost bought one but then I keep thinking I don’t really need it. I have everything I want in my Samsung Smart TV, especially Plex which I use the most, and the only thing that makes me consider an Amazon box is the Amazon TV app on Smart TV is a bit rubbish and stutters (unlike other apps. I’m sure Amazon have crippled it deliberately).
The Fire stick still needs a power socket by the way. That also puts me off either option as I’m running out of sockets, even with two power strips, and want less cables not more.