pretty much everything except PSX emulation is better in the 3DS, specially the new 3DS, PSP struggles to run super FX games on SNES at a good framerate, the 3DS has bearly any issue and the new 3DS is perfect, GBA is also miles better on 3DS, PSP does well, but graphical inaccuracies and games that are incompatible arent rare, as opposed to the 3DS, that provides the same emulation solutions that the PSP had plus super accurate emulation using mGBA (which isnt as polished but the games it does run well it runs perfectly but also uses a ton more power, therefore requiring a new 3DS to run well) or partial emulation, since a chunk of the GBA is already one every 3DS model, so using a VC injector leads to games pretty much running flawlessly (with a few exceptions such as games that need special carts and stuff)