Just thought to add one more thing to consider is that iRex rumored to have an 8" reading device in the works:
https://www.mobileread.com/forums/showthread.php?t=52910
So that is also worth considering...and I will add from all the reading I've done about devices, other than price, people who have and use the iRex devices are extremely pleased with them despite the cost. I have a sense they also are using them not as just casual reading devices though which makes the other features much more important and worth the cost.