To my understanding, NSUI is much more limited than this when it comes to options for screen brightness. I never used it, but I believe it utilizes the same firmware Nintendo uses for the Ambassador 3DS games, and those set the screen too dark for my liking.I thought the same thing and bought a used O2DS. I haven't tried OAF yet but using NSUI injects I wasn't impressed at all. Especially after playing my actual GBA carts on a DS Lite, which is super crisp and bright. From my experience, if you want visual quality, go the DS route, or emulation. The RG351V has served me well for GBA games. Considering the DSi XL route as well. I hear they have great screens.