The .EMU apps do seem more plug and play - but the options available in Retroarch are great.
The main reason why i prefer Retroarch, is that's the only way to play most heavy arcade titles with Final Burn Alpha core.
Standalone FBA port - aFBA is outdated, and MAME4droid use very old set 0.139.
So Retroarch is the best option on Android for arcade emulation.
I also recommend you to check nice frontend app - Arc Browser.
You can configure it so that it uses Retroarch cores directly from it. So, you don't need to start Retroarch, don't need to select core, you just select a game to play and it start all automatically.
It has nice customizable interface and all main frontend features like scraping box art, screenshots and more.
The developer constantly improves it, listening to the opinions of users.
For example, recently he fixed a bug about which I told him, as well as added a couple of ideas suggested by me.
It took only a couple of days from the moment I wrote to him on the forum, and he already released an update.
How it looks like on my gpd: