Assassination PvP?

How do Mutilate rogues fare in PvP on 3.3.5? Although I have no PvP experience on WotLK whatsoever I get the vibe it in't as optimal as Subtlety. Yet still, how good is it really?

I'm going to limit my concerns through a few questions:
1. Does it have any noticeable bugs that cripple the spec capabilities? I heard Envenom used to be bugged.
2. I'm aware it lacks mobility compared to Sub due to missing Shadowstep and probably less instant burst due to no Shadow Dance, but does it have anything to offer in PvP that Sub doesn't? Assassination still seems somewhat burst reliant due to how Cold Blood and Overkill work.
3. How does Assassination compare to Sub in terms of gear dependency and skill ceiling?
4. What is Assassination's main PvP stat?

Likely I'll be playing Mutilate regardless unless the answer to my first question dictates otherwise. I might be asking a lot but I'm fairly curious here, so any answers are openly welcome. :)

Well, in order to give you the right answer, I'll start by saying that there is a gameplay difference between the two specs, which also defines what each spec's job is.

Assassination is more about pressure and less about burst. Assassination's sustained damage is higher than that of Subtlety, but its burst cannot compare to Shadow Dance. Subtlety, on the other hand, struggles to apply enough pressure in order to force enemy cooldowns, but once it does so, it can setup a kill far easier than Assassination.

Overall, Assassination is straightforward and easier to play. Subtlety, however, is better at doing the job, more mobile, and better at higher rating. Try both and see what fits you better. Personally, I prefer Assassination because I'm a casual when it comes to PvP and Subtlety requires too much of my focus and nerves. Assa still gets the job done, even though not quite as well as Sub. As a casual, that's enough for me.