While things have come a long way in the past few years in regards to dirt cheap, somewhat powerful SoCs being prevalent note that GBA.emu requires *WAY* more power to run full speed. On my ancient Xperia Play overclocking the CPU from 1GHz to 1.6GHz isn't even enough to get 60FPS under GBA.emu, while I can underclocked to 584MHz and get full speed under MyBoy!
I would also advise using MAME4Droid Reloaded over Final Burn Alpha, as FBA tends to have shitty problems with buffer under run with sound so things get "crackly" after 30 seconds or so.
And in regards to the original question, I had fun with Chaos Rings, Bard's Tale, FF4: The After and Final Fantasy III on my phone.