If you already own an android phone, or an iPhone, go with the make of what you have.
If neither, think about the phone also. All my Android apps can be installed on the Nexus 7 and my phone with out repurchased.
If you are thinking that you will use the Nexus or I pad as an e-reader, spend the hundred dollars and by a proper e-reader with eink. The color screen, glare, and poor resolution in daylight make a color tablet a poor reading device. I get eye strain quickly while reading on my tablet, so also bought a paper white.
Edited to correct stupid spell check