[Quoth]

I like the new Themes feature. I think X-ray is a marketing gimmick.
I'm not fussed on inverted. I hated that in old B&W / green / amber DOS CRT days and hate "dark" themes on GUIs. I also edit Console windows to be dark text on pale backgrounds (sepia + dark brown if white and black is too harsh). The Aldiko app on Android for eReading does a nice sepia tint background. Obviously impossible on eInk without RGB or orange LEDs frontlight.
Also prefer Whiteboards to Blackboards. I don't find it any help in dimmer conditions.
The only thing I ever saw with inverse that I found easier was the BBC PPM (white needle and digits, black background). It used very bold text.