I had a N7 (the newer model) and enjoyed it but ultimately decided the iPad mini was just better. I think Android is better on phones and I MUCH prefer my Note II phone over my iPhone. I only have the iPhone because work pays for it. However, on tablets, it is a different story.
My biggest problem with the N7 was the lack of responsiveness in the touch interface. I could pinch open and closed to zoom and while doing it notice a split second lag. For example, while pinching, my fingers would have to move a bit before the screen would actually register that I was pinching. Its kind of hard to explain. On the iPad mini it almost always feels fast and smooth. I've noticed this lack of responsiveness on every android tablet I've used (but strangely, not on the Android phones I've used).
Another issue is the form factor. I just prefer 4x3 for tablets. I do a lot of web consumption and reading and I think 4x3 is just better for this. Yes, movies are better in 16x10, but for me, movie watching is not as common as web surfing.
There are more and better tablet apps for the iPad. This isn't a huge deal, but I notice I use more apps on my tablet than I ever do on my phones. I think I mostly just use the smartphones for portable web access, but with a tablet, it feels much more natural to do a lot more. Another advantage to the iPad mini.
I actually found the battery life to be pretty good on my N7. I'm surprised to read so many complaints about it. However, like all Android devices, it sucked on standby time. Ugh! You shut off the screen on an iPad and turn it on a week later, and its still almost the same battery. You try that on an Android device, and it wont turn on, because the battery is now dead.
Anyway, for me, while Android is much better on phones, it just doesn't yet hold its own on tablets.