Paladin and Dark Knight

[Anubis_Nephthys]

PALADIN : Great defense, no problem to manage TP (like the MRD) or MP (like the DRK), only one rotation
DRK : Technical, many CD, classy with his greatsword.

I prefer DRK but i play both...

Your PLD info is wrong...
PLDs are the only class with a significant resource issue. WARs have equilibrium, and DRKs run out of TP way later than PLD (Their MP argument is moot because DRKs keep their MP up). Why do you say only one rotation? PLDs have RH, RA, GB just like WAR has BB, SE, SP.

[Fernosaur]

I have mained Paladin for a year now, and I can tell you it can get boring at times. HOWEVER, as someone pointed out before, the simplicity of Paladin's damage output allows you to be very aware of your surroundings and the needs of your party. It's also the only tank that can offer immediate emergency support with Divine Veil, Stoneskin and Clemency, so it has that going for it. Also, Cover has niche uses but when you pull it off it's a satisfying skill to use. WAR and DRK can mitigate damage for the party but it's less direct than Paladin's soaking mitigation tools. Not only that, but I have found that Paladin's self-sustainability is almost uncompared, even if people tend to give that title to Warrior. I have soloed bosses in daily roulettes due to healers dying to mechanics and the like, and I fondly remember a time in which another PLD and me cleared the last boss in A6 without healers by timing tank swaps and using Clemency. There is a lot of fun to be had with Paladin!

That said, I've found myself more and more put off by playing Paladin in daily dungeons and the like. A large factor is that I think Paladin contributes awfully little in trash pulls. Your AoE solutions are Circle of Scorn and Flash, but one is in a 30 sec CD and the other deals no damage. I'm a firm believer that not doing any damage to mobs is a little bit of a waste of time, so keeping hate in large pulls as PLD is becoming increasingly hard as ILs raise (I stopped playing for a couple months and now everyone is higher than me).

That's why I started levelling DRK. It has much better AoE input than Paladin, and as everyone has said, it keeps you busy and with your attention heavily focused on your hotbars. While learning the job I've had some trouble paying attentions to boss mechanics and the like, but I'm quite fond of how it plays and how micro-managey it is (this coming from someone whose favorite DPS class to play is Summoner).

By now you have probably chosen your main, but another piece of advice I can give is that since the current endgame gear is shared by all classes of the same roles, you shouldn't be afraid to level both DRK and PLD to 60 and use them in scenarios that make you feel more comfortable with one job or the other.

[Maero]

Dark Knight is by far more enjoyable but PLD is easily the easier of all tank jobs

[Drkdays]

Before they buffed pld agro skills I'd have said drk is actually easiest to tank with since unleash is such an easy and satisfying and effective skill to spam, but now they're about even. Though it's rare to find a drk who doesn't use unleash enough while pld who under use flash are still common. As for survivability they're pretty close.