My advice is if you have the extra $50 or $60, go for the FIRE TV. You WILL be happier.
Why not have the best?
The FIRE TV offers twice the RAM Memory of the Stick, and it offers both Ethernet and USB access. Those features give it tremendous versatility, and accessibility not available with the FTV Stick.
As a wireless only device, a FIRE TV Stick's connectivity is only as good as the strength and proximity to the WIFI router. And even then, the connection will never be as solid and reliable as one that is hard-wired.
With all that said, the Fire TV Stick is a TREMENDOUS device at the price. And at $39, it is DEFINITELY superior to the Apple TV in terms of its ability to play and handle video of all qualities.