Are you planning on just "chipping" or chipping/shredding? How large diam. branches? From what I see, online, if just chipping, the DR looks like a reasonable match but, at the max of your hp if your pto hp is 19. The Mighty Mac spec.'s don't seem very clear, or maybe I'm not looking at the right unit.
Have you physically seen either of these? A DR warehouse is 10 min.'s from where I'm working (showroom is about 45 min.'s away). If I can get a look at one, I'll pass along what my impression is. One thing I couldn't find out online was how many knives it uses. So, I just called them. It's a single. They say they tried a 2 knive version but it did not work as well.
Hopefully, others have more experience with pto driven chippers.