Giving tanking a try for the first time...

[Spartan926]

I would definitely say that PLD/GLA is the easiest tank to play, their AOE grab hits in a circle and the added bonus of the shield for armor makes them the easiest to play but also the most boring (IMO) tank to play. In addition they don't really get a damage AOE, flash can only blind enemies and that's not until after lvl 30 I believe (could be wrong on this point. Been a while since I played my PLD.)

WAR/MDR requires more skill for end game content but you get enough practice with it in most dungeons that you'll be familiar with your abilities. It's also a lot more fun to run through something smashing an ax into their faces than it is swinging a sword.

In comparison the biggest difference between these two (while leveling) is in stats and their AOE grab. WAR/MRD is a cone in front of them that deals damage while PLD/GLA is a circle around them with no damage. Most other abilities they get will follow a similar pattern, both (and the DRK as well) rely on stringing enmity combo's together to build threat. Both have defensive "Oh s*#$" cool downs that can be relied upon if things go badly or you need to stop a Tank Buster.

I would not recommend DRK for your first tanking job because it starts you at 30, and it's so radically different from the other two Tank jobs in terms of what you need to keep up (MP and TP, instead of just TP).

The only really important cross class skill is Provoke, which will put you at the top of the Threat lvl bar for the party (but only just). It's a great ability for grabbing aggro if you die on a fight and are resurrected, but if must be followed up by a hate grabbing combo almost immediately or you will lose aggro again.

Important side note: Whatever you do please PLEASE make use of the Hall of Novices, this may seem basic but I've seen a tank run through Sastasha(?) without the basic gear they give you for completing the tutorial.

Hope you find at least some of this information useful in making your decision.