Currently there is a nice selection of cores: https://buildbot.libretro.com/nightly/dingux/mips32-odbeta/latest/
But are there any plans to expand these any time soon?, an fbneo core would be an absolute dream for example as there isn’t a great standalone option on the system at the moment.
Actually, just seen we now have Mame 2003 and 2003 Plus, also excellent news. 
Okay, I’m not sure what magic sauce has been poured into this mainline kernel combination, but the performance I’m seeing from the 1Ghz MIPS JZ4770 now is really impressive for what it is, and my RG-350 is giving my RG-351M (running the latest nightly Lakka) a real run for it’s money with many of the cores.
A real triumph tbh, and to stress it’s how it ‘feels’ to play which is the main eye opener.