Yeah, the plinth is good, although I would have preferred to see him centrally placed on it. The mini is a bit odd, though. Why is the face apparently grey? Also, the highlighting on the knees is a bit stark - a touch of blending would do wonders.
I'm embarrassed to admit that I had to look up the word plinth in order to answer your question. I think the "base" looks awesome. I give it an 8. However, the figure is lacking. His face looks good, but the tunic is not so good. The highlights are just too stark. Also, the hands appear to be of a different skin tone. It's not a bad job, but the base is definitely the highlight of the mini.