Let me start of by saying that I love Mutilate. I honestly think it is the best "do it all" spec. It is great in PvP, leveling, instances, etc. I was hoping that I could keep that spec because I had heard that its damage was close to Combat daggers. This is just not true. Combat Daggers easily surpasses Mutilate in DPS.
I was really becoming quite depressed. As a rogue, all we have is DPS. Our CC is decent but not fantastic. But in so many instances, others were out DPSing me. I felt that either we needed a buff or some other classes needed a nerf. Would people only want Rogues to LP chests and doors for them?
But there is a lot in a spec...and while I still think there is some balance that needs to be worked out, it isn't as bad as I thought before.
While theorycrafters would want numbers...I really don't have that. But I was running instances all day with a warlock friend of mine. In the morning I was spec'd Mutilate and he was easily out DPSing me. I tried as hard as I could to be doing the highest amount of damage possible but he had no trouble out pacing me. He got offline so I respc'd Combat and when he got back on we ran some more instances together. Because I was generating so much threat so quickly I had to hold off on using Blade Fury and Adrenaline Rush so that the poor tank could keep aggro. I was easily able to out pace the Warlock even without using those. I ran a few other instances and felt really good because everyone was blown away with the DPS I was doing.
In any case, I have to say a fond farewell to Mutilate. It was a great spec. But I really like to be optimal when I am playing a class. And while it isn't really surprising...Combat is still the king of DPS.