Okay, here's a question, do cameras in general apply JPEG processing to RAW Files for display on screen? Because White Balance settings have an effect on shots when I'm reviewing them on my screen but when I load them up into aperture, you can lift off all adjustments, and they look different than what I remember on the screen. Could be what you're seeing here.
What kind of Post Processing are you each using?
The thing that strikes me about the pictures in the link you posted is good low-light performance. In particular these two pictures:
Protester | Flickr - Photo Sharing! SB | Flickr - Photo Sharing!
They have high contrast while retaining detail in shadow. That to me was impressive, but nothing I saw on that page looked different from any other dslr shot I've seen. Additionally, most of the images aren't posted in full resolution, so you can't really examine them in detail.
Another thing that might've been overlooked here, is that you're shooting APS-C with zooms and a 50mm prime, and he's shooting FF with a 50mm prime. To even up the playing field photographically you need a 35mm prime. And seeing as how you just posted what you did above, make sure to crop his images for equivalency.
In terms of detail, if you crop his images down to APS-C equivalent field of view, you'll wind up with an image of similar megapixel-age. I really think the field of view might be a bigger deal than you realize.