If you find yourself using your normal swing far more often than skills, then DPS is better.. if you find yourself mainly relying on your skills, then damage is better.

For instance, on my Sorc when I was leveling in WT4, I was using all AoE skills + heal. I used Kelvin's gun rather than my clever flamestrike because the gun does 30 more damage which made my skills do a lot more damage and that's what I was relying on to do most of my damage.

On my rogue, I like DPS over damage because I'm almost always spamming my normal attack.