I took some pictures of the Libra side by side with the Oasis 3. With the light off, the screens are pretty much identical (fonts are slightly different, because I couldn't get even Caecilia or Georgia look exactly the same on both, they render a bit differently). The fonts on the Oasis are very slightly darker/bolder, but on the Libra very slightly sharper (the difference between flush and recessed screens, I guess. The Libra screen is capacitive too, not IR).
With the frontlight all the way up in a dark room, I was in for a shock.
My Libra looked GREEN. All the way green. It's nowhere to be seen in normal or even dim light, only in the dark. Still, it doesn't really bother me. But it's the first time I've seen a green screen on an eink reader.
As to the warm light, cranked all the way up it's pretty identical orange on both. I didn't manage to capture it in a photo, though. It looks much yellower on photos than it does in real life. I included one photo with the warm light up,
but it should be taken into account that it looks much more orange to the naked eye.
The Libra is on the left, the Oasis on the right. The first photo is with the lights off, the second and third with the light maxed out (warmth off), the fourth with the light about halfway up (warmth off), the fifth with both light and warmth maxed out.