I'd say they are very very different from each other
black dog is tighter on the low end, a lot middier, rounder on the top and more opaque sounding instead of transparent
definitely a more modern sounding, but I wouldn't call it a muscular mule like the sites description
the mule and riff raff can do modern pretty well too, but with different results
I'd say the riff raff is the most versatile between those