It's...fine.
Tolerable experience, at least on the mini, if you've never held a DS in your life kek.
You can absolutely feel the 2 frame being buffered the keep the displays in sync.
Also side by side with the rp5 screen like this, the kinda crappy PWM frequency of the mini and classic screens becomes apparent.
Above 60% brightness is fine, any less and my eyes start feeling dry.