For this, check out Splashtop. I've been using it for years and it works great. They even have Win8 touch integrations so you can play Civ 5 touch, and an OS X client so you can use a Mac from a tablet or phone.
Splashtop does work with OS X, tablets, and phones, and also works over the internet (with additional latency obviously). I'll give Steam's streaming a shot sometime soon.
A better comparison would be against Steam's own streaming, which I haven't tried.