DEATH KNIGHT QUESTION?

hello all i quit wow for a while and have recently just started ive got an 85 mage and 85 rogue but got bored and decided to lvl a death knight now on lvl 81 and i was thinking the dps was a tad low compared to my other classes i did some research about them and watched a few videos and none of them seem really great on the dps front i want to pve a fair bit on him but also want to pvp i would just like some information bassicly are death knights still good and whats the best spec for lvling (currently using unholy) are they still a respected class in the raid scene i mean as in not frowned upon for coming as dps and not tank like palas use to be :) i just really want to no are they good in raids and is it possible to keep up with mages etc in raids as a dk thanks all :)