i swear by chromecast. but im sure apple tv, firestick, etc are just as good (and fire stick with kodi is a whole nother beast)
i will give you a quick rundown of chromecast and apologize if you are speaking specifically to firestick
i cut cable 6 years ago. i bought a chomrecast. i pay for cbs all access, netflix, hbo, pandora. plug little piece of plastic into my tv usb and it turns it into a smart tv. my tvs were already smart tvs, but using the apps through the tvs is harder than via the phone. when u have a chromecast plugged in, a little chromecast icon appears on most apps. with a touch of a button, whatever im using on my phone is now playing on whichever tv i want. i use youtube alot bc i subscribe to alot of channels on it
its HD. smooth. pretty awesome
and outside the legit apps i mentioned above, i also throw stuff to my tv's straight from my pc. each sunday, for example, i watched dragon ball super anime (english dubbed). just like witht he apps on the phone, my browser has a little icon that, when clicked, makes yyour computer screen appear on the tv
this is obviously useful to stream MMA. not that i would think about doing that