It would be worth it to play some games with motion control, with the SP the games are upside down and pretty much uncontrollable. Kirby Tilt 'n' Tumble for the GBC comes to mind, though it's a GBC game I don't know of any backlighting available for the GBC system. There's a few motion control games for the GBA but I don't know if they can be set up for both the original and SP or just the original.
I have an original system and an SP, but I like playing games on the DS. The backlight is way better with the DS, though I haven't tried the brighter SP and I don't want to bother tracking one down.