I have 5 lvl 50 characters and recently I have been playing my Guardian tank a lot. Prior to that I was trying out tanking on my Vanguard. When I finally made the switch to play on my Guardian I came to the simple realization that it is easy mode on my Guardian. So much utility. The biggest differences are the fact that the Guardian has a million stuns, cooldowns, a push, two leaps, three if you include the leap after the push, an aoe slow, etc. None of my other classes have as much utility on top of raw damage/defensive ability. And don't even get me started on the Smash/focus spec. So when are the balance changes coming?
A million stuns, lol. Two. If you go full Defense. Which almost nobody does because Unremitting is a must as is Commanding Awe. Otherwise a total of one hard stun. And very little damage, significantly less than either of the other two tanks.