Sin dorei

So I hear Shadow Priests are lagging behind the other dps classes.

personally i think I'm doing good. What do you all think of Priest dps?

I find that shadow dps is probably on the lower end of the dps classes (even for a hybrid). You can still do good damage, especially on encounters with a heavy amount of AoE, but all other things equal (gear, skill, exp with the encounters) you will lag behind. You will notice the damage falling back as you get better gear. You will stop scaling as well as other classes.

Shadow priests make up for this with a tremendous amount of utility: buffs, replenishment, the capacity to heal in emergencies, minor heals to the party while doing damage, MC, etc. However, I do not know if these are any better than what another hybrid dps can bring to the table (Ele Shammies, Boomkin, and Retadins for example).

Still, we are generally lacking in replenishment classes in our raids, so this alone, with reasonable damage, would make you a welcome addition as a shadow priest.