Do you really worry about battery life with your Nexus? I have never owned a device that does this much and lasts so long. The book I am reading now I read in landscape mode. I only lose two lines of text per page. I am not a big reader but what am I missing here?
It's all a matter of how long/much you read. The kindle will
last for at least a week or more of heavy reading (8 hours a day) without needing a recharge. You get spoiled by that. Yes, I will often sit and read for 4 or more hours. If the Nexus 7 battery is partially discharged already, it will run out. So I must go fetch the charger setup IF I am close to a plug. When away from a plug, forget about it !
I just don't ordinarily worry about the battery on the kindle but the N7 will need a charge every day with heavy use, sometimes twice.