Hmm. At least in the US, Apple Maps gets their business info from Yelp, so it tends to be about as reliable as Yelp is. In general I find Yelp to be mostly on point -- not perfect, but not worse on the whole than Google.
In my experience, I find Google business hours to be more accurate than Yelp. Not sure why, but I think restaurants find Google easier or more important to update when they adjust their hours slightly.