The emulator has a pretty high compatibility rate, which means that practically every game will work correctly. That said, the fluidity of most roms depends on your Android model. Some games are pretty demanding, and if you have a device with less than 2 gigabytes of RAM, then it's possible that it might go really slow. In these cases, you could try to deactivate the sound, which normally helps the games' performance.
As usual, NDS Boy! doesn't come with any roms. You can download the Nintendo DS roms from any one of the many pages that specialize in them. That said, while the emulator is technically able to play files in .nds, .zip, .rar and .7z format, it's only a sure thing if they're in .nds format.
NDS Boy! is a good Nintendo DS emulator for Android that offers tons of additional configuration options. Best of all, it lets you set up the controls however you want.