Quote:
pretty much every mob died within a CS+KS.
This pretty much sums up leveling with Muti. The only drawbacks to Mutilate builds is the dependency on kidneyshot. If it misses, it is incredibly irritating. You have no real ability to take on more than one opponent at a time (lack of blade flurry). It also sucks vs most elites, especially mini-bosses immune to poisons / incapacitates+stuns. Whereas in those situations, combat can easily kill most elites with the help of evasion, riposte & AR.
As for single target dps though Muti is excellent for grinding. Most mobs wont survive for long enough to even hit you more than once or twice. So there is very little down time. It is also one of the very few times you will use remorseless attacks for grinding. The extra crit boost will allow you to CS>Muti>5cp Kidney shot most of the time without having to spec into Sub for Initiative. The 20 second timer also encourages you to find your next mob quick so that you don't waste the buff, which again will speed up grinding.