Pala tanks or DK tanks?

You know I casually dislike paladins for the amount of praise they get compared to the amount of hate people have for Prot warriors.
I'm currently on a Protection warrior 5.2k Gs and I've had lots of trouble getting started into ToC 10 nm and ICC (lots of wipes) and I get called cancerous and broken on Blackrock pvp because I've been a really mobile and a big hitter paired with a good healer.
But once I'm gonna have enough of my lovely homesweet shield slam Warrior I'm gonna level up other tanks
What I have on my mind is Prot palas or frost dk tanks. Keep in mind I've never played any of those but I've heard good stuff from them because of the amount of credits people give to them when they casually drop in Prot warr threads to sh*t on us.
Which is easier for end-game content and which one has more efficient single-target (boss) ultility compared to the other tanks?
I'm looking for a Pure raw Main tank class

It depends on what you're tanking. Both are very strong. DK is generally superior for single-target threat and mitigation on magic-heavy fights. A DK can be very good at multi-target threat too, but not so much if they aren't Unholy. Protection Paladins are by default better multi-target tanks and have great passive utilties to mitigate damage and keep them alive. Which is "better" depends on what you're tanking, how you're tanking it, and often times the two are interchangeable.