I have 3 questions here.

I've been playing for quite some time but this has been one question I haven't ever quite understood. At this moment it's more geared towards the armor you buy with frost. So I know each class has class specific gear however there is also the gear that anyone can buy from the regular frost vendors. Is there a difference between the two? I know my specific classes armor offers extra damage for some abilities however the vendor armor has better stats overall.

Also does anyone know where you get Vanquisher's Marks Of Sanctification? My guild and I have been running ICC 10 man normal so I figure from there on one of the heroic modes

Also what is a good raid add on for dps? I am a Blood DK. thank you in advance
thank you for your response. I should be more specific I suppose. I did make it sound like I wanted something like recount (which I use) I should mean something like Titan Panel. I have tried it but wasn't real fond of it.