Warlock are decent. A voidwalkee with devour talents has great survivability, but god does the jumping ability suck. My first was a titan, they truly just cannot die, but my favorite is my hunter although they die so easily and it seems very difficult to get stats into anything but mobility. I think all the way through leveling I was at max mobility and 0 recovery and a few points into resilience. Also hunters class ability is very disappointing. Maybe if it gave you a longer invisibility or buffed you to take less damage for a small period it would be more viable.
All in all, if you can get past the weak jumping abilities of a warlock (which I cannot), you should enjoy them alot, they have great abilities and seem pretty well rounded for both PvP and pve.