I played unholy mostly during dragon soul to great success, generally always topping the charts or being very close, and ranking on numerous boss fights according to world of logs. So I feel like I can handle the spec, yet now when I run dungeons or LFR I seem to be lower then I want to be. I guess it's probably my gear since I still have a bunch of blues, especially my weapon, and maybe some rust since I've played mostly frost this expansion... but is there anything else I might want to consider?
To be honest I've almost gotten to the end of things with my dk. I loved him during dragon soul, but I guess haste plus the set bonuses did so much to reduce downtime then. If I have to go frost to succeed I'll probably move on to another class.