Don't listen to any of this "Combat for PvP/Combat for leveling". Go Watchmen or go home. The self-heal off of burn crits combined with Zen making your next 6 burns crit is disgustingly powerful in all fields, be it leveling, flashpoints, or PvP. I get at least 30 stacks of centering every fight while leveling, and a lot of the time in PvP. My suggestion for centering is to "save" it until you start a fight, leap in, pop overload saber, pop zen, one enemy dead. Then over that fight it builds back up to be used for your next opener. In PvP Zen is even more deadly and really fun to use. You can use it when your going in, use it when your opponent escapes, has low health, and still has burns on them, use it when your low on health. Once you get high enough in the Watchmen tree you get two centering when hit and two centering when using a focus spender. It builds up insanely fast AND it heals your party. Nothing like tossing out a small heal/major damage buff during a big push. Now some people may complain about the "ramp up time" on Juyo form. In most PvP games(excluding nod camping and death) I never lose my Juyo stacks because I am always in the thick of combat/looking for my next target. Sentinels are great for hunting down people in the back lines with low health, Snipers who aren't in cover, and at killing SW/BH. Heavy armor doesn't save them and its an absolute joy to watch these heavy armor wearers health deplete itself as your burns go off. Yes Sentinel is hard to play, yes it has lots of abilities, yes its a good idea to get a Razar Naga(which I don't have...LOTS of keybinds and lots of ctrl+ keybinds for me), but once you learn to play this class and fall into a good rhythm you are a force reckoned with.