Wanted to add my 2 cents.
I bought a n3DSxl, my first 3ds in years.
The unit was IPS, top screen. 3d effect, godly. The head tracking really works. Dark blacks and extremely nice viewing angles.
I was happy, or so I thought, until I had to return the unit 1 week later due to a bottom screen defect. I get a replacement, same color, red.
Open it up and the difference is immediately apparent. The new one is a TN top screen. Ok, so at first glance, it is noticably worse. Mainly, because viewing at any other angle than head on isn't going to work. The screen gets bright as shit. Also, I noticed there is a very, very subtle flicker effect when moving around the unit with 3d on. Yes, even with head still in view.
So first response was, yeah, I just fucked myself over and downgraded.
And THEN, I started playing. Like, real world playing, head actually facing the screen, not fucking around trying to screw with the 3d effect, etc, the whole 9.
Gameplay is brighter. Does that mean more "washed out." At first I would have said yes, but bear with me. Darker blacks may give the illusion of being more 'vibrant', but is that true to the source? After real world testing, I'm going to have to give a resounding NO.
I was playing Xenoblade on the defective unit for over 5 hours. One of the things I noticed was how fucking hard it was to see the little exclamation over the people's heads who have side quests. Partially due to the resolution no doubt. But on the New TN screen? I see it all. I see everything. The colors aren't more "washed out," in fact quite frankly they aren't being crushed by too dark blacks anymore.
Then I kept playing. I see more details in the environment and characters.
The illusion of vibrancy was just that on the IPS screen-- an illusion. The reality is both screens have shit tier resolution, and therefore the black levels are of the utmost importance in order to see any details in game that aren't directly in the light.
In the end? Neither is perfect. Take them both side by side and 9 times out of 10 I would say first responders would choose the IPS, especially if they move their heads around. But sit down and play, like you really truly would in any real scenario? Sorry, I have to say the TN displays much more details, ESPECIALLY in Xenoblade. So much moreso that I would call it a complete game changer, and Im considering starting all over again.