I can tell you right off the bat that the Nexus 7" only has one front facing camera used for video conferencing. If you want to take pictures with it then it would be very tricky because you would have to point that front facing camera at whatever you want to take a picture and hope that you lined up everything properly.
The Asus has both front and rear facing cameras. The rear facing camera is 5MP while the front facing camera is 1.2MP (same for the Nexus). With two cameras that means you can actual see on the screen what you are trying to take a picture of rather than point and pray for the Nexus 7.
Both uses the same Integra 3 chip from nVidia and both have the screens with the same resolution so the gaming performance will be the same. Naturally things will look bigger on the Asus.
Reading and browsing should be easier with the Asus because of the larger screen. I think the choice is clear since you want to use the tablet as a camera.
I have a 2012 7" Nexus. I like it because of it's size. It fits in my jacket's inner pocket. On a warm or hot day I can simply stick it in my jean's back pocket if I need both my hands free.