PvE - Warlock, both sub classes shine.
Raid - Depends on the job. Hunters are OP during Atheon and Supplicants with Golden Gun. Titan are workhorses and the catalyst to make the team way better with Ward of Dawn (bubble), Weapons of Light is amazing, when your Ice Breakers is criting 17,000+ damage per shot on Atheon, it's ridiculous, I have done 6 crits in a row and just saw Atheon's Health melt. Warlock are your safety net, Sunsinger subclass is the go to during raid, it's literally a life save for the player and raid team
PvP = Hunter shines here, if you have the right set up, you can pull out roughly 3-4 Supers (Golden Gun) per match, it's insane how agile and speed really do help you out
Titans come in next due to defense + health, Warlocks are no slouches but most Locks get wrecked by their jumping ability, the hovering plays a huge part in your downfall
My Main Warlock, I just enjoy it too much, but PvP it's Hunter, Titan is good on both sides, not great in one bad in the other like the other 2 classes