It would be interesting to revisit this comparing reality vs “Groung Truth Ambient Occlusion”. http://iryoku.com/downloads/Practical-Realtime-Strategies-fo...

Also, it's not entirely surprising that AO wall corners don't match his living room. AO models an environment with light coming in from all directions uniformly --as if you were inside of a giant, glowing white sphere. His living room walls may be lit indirectly. But, there is still a lot of directionality to the bounced light.