The normal stick is bog slow, I got fed up using mine. Get the 4K stick as the processing power makes it useable for normal use. Personally though these days I just stream to a Chromecast from my phone or tablet.
You can also link the 4k Firestick to an echo and use the echo as a speaker through the Home Theatre feature, which you can't do with the regular Firestick.
You can also link the 4k Firestick to an echo and use the echo as a speaker through the Home Theatre feature, which you can't do with the regular Firestick.