I believe it is personal preference / play style. Also, PvP / PvE? Jugg tanks are all around brutes. They are annoying to anyone trying to bring them down , and have great survivability as well as some decent stuns and DPS. Assassin tanks are squishy, but to compensate for this they have a shield generator which absorbs a very hefty amount of DMG. Assassin tanks are meant to be more stationary , and are not as mobile as the jugg tank. Juggs can leap to an enemy , then intercede back to the healer. Sin tanks feel slower, but they do have a pull, and some slows, and a stealth in/ stealth out option for the heavy firefights. The one great advantage a sin has, is the AOE heal buff/ teleport. If your healer stays within range the sin tank gives +5% healing increase which is huge in the long run. Then again most warzones are mobile so you'd have to re cast and drop the AOE and watch a lot of buffs. Juggs are simple easy and fun. So it all kind of depends on if you want to sneak around and support your healer. Or be the pestering bug jumping and stunning everything. Haha good luck !