I've gone through three of these displays so far.
Two of them feature an obscure bug whereby powering on and back on quickly can result in a black screen with no backlight or image. Sometimes this resolves when proceeding to the cartridge boot but not always. The solution is to power the console off and back on again. It can also happen occasionally, when cold booting the console. Because it happens at the very start it's not that big an issue. However, this can also be the case when awaking a game out of sleep mode. Everytime the display is reset in this way, the backlight brightness is also and needs readjusting.
One of the displays had a brightness issue whereby the screen would spontaneously flicker for a fraction of a second. This happened on average every few minutes but sometimes it could be several times in one minute. Had to get a replacement for that.
The displays setups had their ribbon cable and GBA motherboard changed out in an attempt to resolve the aformentioned issues but it was no dice. The power-on issue appears to be a quirk with this brand of display in general.
When it comes to looks, the display looks stunning. The colors and pixel delimitation are very good, with no grid spacing left in between the pixels.
There is some slight ghosting, particularly noticeable when an element is moving against a solid color background, and also with flickering images. Something like an NES emulator that can cause lots of pixels to flicker at full brightness due to resolution misalignment will leave a ghosted effect on-screen for up to 30 seconds but even with GBA games you can see ghosting, such as bringing up the menu in Castlevania: Aria of Sorrow in the Top Floor area with the flickering moon in the background. The effect's persistence depends on the intensity of the object's brightness(the red moon isn't that bright) and also the backlight brightness matters.
Depending on brightness, the screen will end up either draining your battery much faster(up to twice as fast) than the original display on default or max brightness, or considerably slower than the original display. As such, soldering the wire to adjust brightness is definitely recommended. If you further combine this display with a flashcart - which further tend to drain the battery faster than regular GBA games - then the battery can end up lasting as little as one hour, even with a fresh replacement battery.
The conclusion is the screen looks good, but a few quirks with powering on and ghosting keep it from being a no-holds-barred choice. Furthermore as mentioned I had one display that was defective. I'd like to stress that despite all these issues, the Retromodding team did an absolutely stellar job, staying with me through a 2-month ordeal that involved 3 separate displays, until everything was sorted. Even so, you might want to look to other third-party GBA displays for less glitches and maybe better power consumption. If you do decide to go with this however and you understand its quirks, it will not disappoint in terms of image quality.