Which portable emulator would you recommend in terms of quality and price?

Hi, I want to buy a portable emulator but I don't know where to start looking. I'd like to be able to play PS1, GBA, DS, and some N64 games. I'd also like to know if it can emulate Pokémon fan games, which I currently need Joiolay and RPG Maker to play on Android. What do you recommend? Thanks!