Best setup for mostly Kodi and occasional MAME gaming?

I mostly use Kodi as a DVR frontend, which works great. I also have retroplayer uSD images which I sometimes boot into. But, I would like to combine those two things together into a single OS. There are many blogs/guides/comments from people doing this over the years, but it’s not clear what the current ‘state of the art’ is.

Kodi 18 / Leia reportedly has retroplayer integrated ( Congrats on the Retroplayer merge! ). Is a test build of Leia the way to go?

Or, am I better off with an add-on to stable OSMC+Kodi? If so, any pointers to setup guides?

RetroPlayer is still beta and being tested. Head over to the development thread and you’ll see only few emulators are working already.

If you want something to use now, I’d say go with mcobit’s integration of RetroPie into OSMC. Follow the instructions in the start post of the RetrOSMC thread and you’re good to go.