Wow! I'm not a big streamer... I have a pretty small apartment; and outside of PS4 remote play right before bed on my Vita, I don't really understand the point. But gotta say, Valve's implementation is damn near perfect.
My desktop is my host machine, and the MBP is receiving the stream. Log in on the laptop, and all my games on my desktop are listed. Click one... and it asks if I want to stream. I say yes, and boom, I'm in.
And the latency is VERY low, and the quality is surprisingly nice.
Took a quick YouTube video. The desktop is plugged into my router/modem via Ethernet, then my MBP is connected via WiFi (Wireless N).
https://www.youtube.com/watch?v=jly7aPpJe2M