OK well for those that see this as a Nikon bashing then fair enough, lets make it one!
Regardless of how good or bad the sensor is, if I as an reasonably experienced amateur photographer can't pick up this camera and get good shots out of the camera in a couple of hours, then the camera is poor (again IMO!). Furthermore, no matter how good a sensor is supposed to be if the camera can't process them to give me a reasonable result on basic settings without digging through menus or going away from standard picture styles, in my mind it is a poor camera. There will be many that will be disappointed with the results if that is a representative example of what to expect from it. I am not typically a brand fan-boy and I respect Nikon for producing some great products that I've considered strongly for various reasons.
I looked back through my Canon 450D photos with a kit lens and out of the camera jpgs are much more pleasing and easier to work with than these were. Look back at my photo of them month winner from years ago, that photo was taken with the 450 and kit lens on my very first day with it when I knew nothing! And the result out of the camera was pretty good. If these photos above are representative of what a D5100 produces, well I made the right choice way back then.
At the end of the day, my point still stands, lab tests like this that put the likes of a 5D3 on a overall par with a 5100 or in this case put a 5100 well ahead of a 7D are a waste of time because as I've demonstrated either through fault of the camera, or fault of my ability to use the camera in the real world the results will be wildly different. Even if you choose to believe the results regarding the sensor, there is much more to a camera and the resultant images it produces than just the sensor.
Just my opinion! Flame suit on!