Super Mario Land's default color scheme on the SGB is very nice to look at since it works good with both foreground as well as background. But it will still provide only four colours simultaneously on screen for monochrome GB games. Unlike the GBC which can get 12 colours on screen for the same games. But unfortunately doesn't support SGB's fully customizable palettes (only a dozen or so presets are available), that's why some non-SGB enhanced monochrome GB games can surprisingly shine on emulators where you can have 12 colours and custom palettes combined.
SGB enhanced games are another story though, too bad there's no support for SGB enhancements on the GBC, GBA and GB Player attachment for the GameCube. Even the downloadable GB games for 3DS (e.g. Donkey Kong) have no SGB enhancements support.