MicroData vs RDFa vs JSON-LD

I have started looking for implementation examples for Local Schema on Wordpress sites... I am not comfortable with leaving this up to plugins, but am still not sure how to properly implement successfully on a few Wordpress sites I am helping out with. During the research I found a few formats for Local Schema that include -- Microdata, RDFa and JSON-LD.. The resources talked about how at one time Google was only really interested in Microdata, but that was on it's way out the door...

So my question is for those that deal offline/local -- How are you implementing local schema data? Which format do you use? If anyone has a video resource that lays out how to exactly do this with Wordpress, that would be awesome!

Thanks for any help,

--Rich