For my part it's a little weird.
I have an Old 3DS XL which is told to be a double TN by 3DSidentGUI, but the colors don't get washed or reverted when I look at a near-to-180 degrees angle.
But more strange, I also bought a few days ago a New 2DS XL. It's also a double TN, but the screen displays more yellow colors. Putting the two consoles side by side, the difference is really important. I thought it could have a problem, so I returned it to the shop but they compared to another model they had (brand new) and told me it was the same. Another vendor I shown the console too did notice the difference even without comparing the consoles side by side.
Today I bought a New 3DS XL (the New 2DS XL didn't satisfy me) and I have a double IPS panel, so of course the colors are better. But still, between two consoles who have a double TN panel, one is far better from the other...
Any idea of why this happens ?
(I don't post photos here because my camera is too bad to show the differences between the screens)