I have a(n admittedly fairly old) Boox and I like it in concept, it's great that I can install multiple e-reader apps and read a book in any format with any DRM, but the battery life and performance seem a lot weaker than the early-generation do-one-thing Kindles.

Which sucks, because the battery life and performance were the huge selling point for e-readers not just being shitty tablets.

Mine is not comparable with the Early Kindles but it comes close to the Oasis with the tiny Battery. I have to charge it every 1 - 2 Weeks. Wifi is disabled, Bluetooth turned on. I only use the Koreader App, sometimes Wikipedia. Powersafe triggers after 24h of inactivity what really rarely happens because I read every evening.

Mine lasts for weeks! I disabled wifi (only on when I need to transfer some books and keep the backlight at a not super high level but am not otherwise careful in how I use the thing or try to preserve battery.