I was PLD main in 2.x and I switched to DRK. I will not be switching back to PLD, so that should give you some indication.

Don't listen to the doom and gloom, especially from WARs. There's nothing wrong with DRK and it will do fine at end game. And to top it all off, it's fun (subjective, I know). But it's more complex and engaging than either PLD or WAR, IMO.