Source: I was the chief hw engineer for this device.
The colors do not invert when the backlight is on, which is great because you can turn on only a slight amount of backlight if you need it, and have it blend to the ambient lighting.
It supports 256 levels of grayscale.
The large battery also helps it last longer and accounts for the much more powerful chip compared to the remarkable
Does it invert the colors when backlit?
It's about 50% heavier than rM2; the battery is almost triple the capacity of rM2; I assume these are related and both due to the use of LCD over eInk?
How many shades of gray?