Pally or DK?

Looking for a character for end game pvp/pve casual play. Debating between a pally or dk because both have the option to tank, are melee, and have dps specs. Wondering what the pros and cons are, and whether one would be better for a more casual player?
For a casual player I would suggest a pally. They're a hybrid and are pretty easy to play. for pvp i like the bubble shield and for PvE the healing.

For DK, i use frost which is the DPS class and the rotation is simple. Im not sure about the survivability.

For Pally, I do less DPS than my frost, but i survive longer with heals.
Pally, way easier to get into tanking as a pally than as a DK, I have no real opinions on pvp.
Good deal, appreciate the information.

I figured DK tanking was a bit trickier than a pally. At least it appears that way.
Though, If you wanna be a DK, make a DK. You can learn, it's not like if pally is easier you NEED to make a pally.
Pally Tanking:
Pros
Rotation is simple and easy to get into
Pally tanks are some of the most desired tanks, due to a raid CD and great survivability

Cons
Perhaps too simple of a rotation, sometimes I feel like I'm just a dps that gets smacked in the face.

DK Tanking:
Pros
If you know what you're doing, you could be an amazing tank, especially if you're just doing casual play
More involving and rewarding, if you do it right.

Cons
Many flawed mechanics, though not as noticeable in casual content
Can be the worst tank if you don't properly research the class and cycle CDs

As for DPS, I personally prefer DK DPS. You'll generally do a lot better with an equal gear level as a DK, especially as frost. The rotation is very simple. Ret is based on a lot of RNG and CDs. You can get lucky and do amazing, or not so lucky and do pretty horrid.

Pallys, however, do have the option of healing, which I would consider a pro as well.
If your interest in tanking is greater than null go paladin. Blizzard will adjust their dps soon. Death Knight tanking is going to be a train-wreck for the rest of the expansion. Paladin tanks are just so vastly superior and have been since Ulduar.
If you tank as a paladin you risk losing your sanity, your life, and your cookies. . . Its that annoyingly easy

Ret is almost as bad, you will only lose most your sanity and your cookies
Id rather have very little fun than mountains of kitten-punching frustration. Go Pallie.