a - GBA Free is a Gameboy Advance Emulator for Android Devices. Many options and fast emulation speed.

"a GBA" appears to be based on Gamboid. Compatibility was good and game play is pretty smooth. Audio, on the other hand, sounds like it is being played through a kazoo.
"a GBA" also require a GBA bios in order to run.
For some reason I was not able to map up, down, left, and right controls to my PS3 controller.
This app does have ads. Not too intrusive and they can be removed with a paid version.
All in all "a GBA" is ok. There are better Game Boy Advance emulaors out there.