I bought a tab 2 after owning the nexus 7. It all boils down to quality. In the month and a half I had the n7 I had to send it back for replacement 4 times. Every one of them had screen issues; screen lift, multi touch issues, unresponsive after using it for a bit(had to turn the screen on and off to make it work again), and dead pixels. My last rma I just asked for a refund, and bought the tab 2. The overall quality is far better, plus an extra camera and sd slot.
That being said, I did love my nexus so I'm not just hating. The nexus 7 is killer fast and already has a massive amount of dev support. When the nexus 7 works right, it's awesome. Unfortunately I got bamboozled by Google too many times to chance another one.
The tab 2 might not have a quad core, but in my day to day use I don't notice a difference in speed and responsiveness. I've also had zero defect issues and the damn thing just feels solid. Thanks to aokp and other roms we get to enjoy jelly bean too. I'm happy with my decision.