I'm a Muti/Assass rogue. Probably sub-speccing Subtlety for PVP but I'm not yet entirely sure on that.
I'm not really sure but Combat rogues are more on consistent damage, right? They're like the maintained DPS spec.
Assass/Muti rogues are more focused on high burst damage or powerful openers with finishing blows.
Sub rogues are more designed for PVP, if I'm right. I remembered seeing them as one of the lowest DPS rates when it comes to PVE. They really more on stuns and escapes.