Emulators:
I mostly use the ones made by a guy named Robert Broglia, they seem to work the best
https://play.google.com/store/apps/developer?id=Robert%20Broglia&hl=en
Peripherals:
I own a Xiaomi Wireless gamepad, but would prefer a Logitech F710.
The sticks are too sensitive for my taste.
Usage:
I use the KODI addon "Rom Collection Browser".
It is old, there hardly is support for it, it takes a while to configre it... but it looks nice and works okay.
Some guy made a few good tutorial vids on YouTube:
https://www.youtube.com/user/jaykresge/videos
Edit
This seems to be the go-to-service instead of RCB now:
http://forum.kodi.tv/showthread.php?tid=287826
If you want to do retro gaming with you original cartridges, i'd recommend the Retron 5:
http://hyperkin.com/Retron5/