There are guys that stack up a lot of fur with duke traps. If you don't already know how to tune a trap, the learning curve can be steep with a duke. You can lose a lot of catches trying to learn to tune traps.
MB traps require very little tuning. Much of this is due to the fact that they come with a PIT pan system. This has the pan tension already set and you won't need to adjust that. Also don't need to fool with the dog. I have only ever had to replace one dog on an MB 550, and that was after a grey fox chewed it, believe it or not. The dogs on 450's will get ruined from time to time.