You might have remembered a thread made earlier this year pondering the differences between Game Boy Advance systems with LCD displays made by Sharp and newer systems with LCD displays made by Panasonic.
I still haven’t gotten to the bottom of it, but it seems likely both companies made screens to the same spec. What is more significant that I was not previously aware of, is the substantial differences in display quality between early GBA systems that shipped with a 40 pin LCD ribbon cable, and later systems with a 32 pin LCD ribbon cable.
Exhibit A: an interesting reddit post:
The early 40 pin GBA boards had much better screens, brighter/clearer reflective backs due to different polarizers used with panels for the more common 32pin boards.
Comparison picture, out of 20 something systems in this lot I got a few years ago, all the 40pin panels were nicer than the 32pin ones, all 32pin ones were darker and with a warmer less neutral polarizer tint. The polarizers are different, you can tell by how they react if you face the GBA against an LCD (polarized light) and turn the system around, the polarizer behavior between 40 and 32pin is different.
Conclusion: The polarizers are better in the 40 pin systems.
Exhibit B: Power consumption tests: Imgur: The magic of the Internet
Conclusion: 32 pin systems consume significantly less power.
Last, a video demonstrating the differences between both:
Hope that helps! I’ve ordered a 40 pin system from Japan, will compare it against my SP. I now wish I hadn’t sold my European launch GBA…