CFW does a few things GW doesn't, like being able to install GBA and DSi games. There's also cheat support with NTR. The latest GW update has cheat support too apparently but they have also issued a warning to DSTwo users which means genuine GW cart users could get caught up in the cross fire. Personally I would just stick with what you've got now assuming you don't need some quick cash from selling it (and who knows if GW will one day crack the 9.6+ keys and you need a GW cart for it).