For those of you who have a PT/Vanguardand a Jugg/Guard, which of those two are easier to tank with at least when gearing up at 50?
By far, the least frenetic tank is the PT/VG. The only thing you have to pat attention to, at all, is just keeping your ammo high. Guardian/Jugg tanks have to deal with watching their resource bar like a hawk and learning to spend and use abilities as the absolutely proper time; it is *really* easy to completely screw up your resource maintenance by using one attack when you should have used another. Because of this, they are the most frenetic to learn, but, once you've mastered that aspect, they're relatively easy. Shad/Sins have to constantly watch their buffs and know a crapton about specific fight mechanics, movement, and ability timing. The skill threshold to be a good Shad/Sin is lower than that of a Jugg/Guard (though it's still more hectic even after you have learned it because it's so proc and RNG reliant), but it takes more to be a great Shad/Sin than it does to be a great Jugg/Guard (the difference between good and great is largely determined by how effectively you can use and abuse your CDs and Shad/Sins just require you know more and use them more often).
So, to answer you succinctly, PT/VGs are, regardless of what level you're attempting to perform at, the most simple and least hectic tank. At moderate performance levels, where all of the tanks perform roughly identically, the Guard/Jugg is the most hectic, followed by the Shad/Sin. At top tier performance levels, where Shad/Sins beat out Guard/Juggs which beat out PT/VGs, Shad/Sins are the most hectic and involved and Guard/Juggs are roughly the average between Shad/Sins and the painfully simply PT/VGs.