AirPlay makes the appleTV vastly superior than the others as long as you have Macs or iOS devices. Second place goes to Roku for making a pretty decent device. Chromecast is pure garbage.
For streaming my own content, heck yes, Apple tv, I agree.
But for streaming services, Roku. Plus, if you have an older tube tv that still has a great picture and works well, the Roku will work with it.