I agree with Babyfacemagee, that reading books is best on a 7" tablet or even smaller. I use a five inch tablet for book reading when I'm away from home. But please, oh please, stop using the term "form factor!"
If you want a bigger tablet, buy an iPad. Best on the market, IMO.
 On second thought, I haven't bought an iPad myself yet, so maybe an open-Android Nexus 9 or 10 would be nice, if it had a great screen like the 7 and was much cheaper than an iPad.