My Guardian is only at 32 (only been playing for a little over a week), but I have been playing MMOs as my main genre almost exclusively for about 7 years. My advice, especially in a game this young, is to play a class that has a playstyle that you like more than anything else. Power comes and goes relative to other classes, but if you love melee characters, but pick another class because it's OP, you won't be very happy when they nerf that class or buff its counter class. This is actually a really fun stage of an MMO, because there are so many possibilities out there with specs and ability rotations! One of the top tanking specs right now is half in the defense tree and half in vigilence! Come up with your own goals in PvP and create a spec around it. Without a combat log and the applications for heavy testing, there is no "cookie cutter spec", so play what you want. Do you want to protect healers/deadly dps on your team? Do you want to be the most mobile huttball carrier ever? Do you want to focus on single target lockdown with stuns, pushes, etc? At this point in the game, find a niche and stick to it. While at any time there is one "top dps", there are things a guardian can do that no other class can. Guard and taunts are insanely powerful. Moral of the story: play what's fun for you!