For starters, the armor is an "upgrade" of your existing armor set - this means to get the full Heroism set (the warrior set) you'll need your full Valor set. You work through the quest chain sequentially (there's a specific order) upgrading each piece of your set (though, no, you do not need the full set to start the first quest). Each step in the quest chain requires a number of quest items as well as a quantity of gold. One step, in particular, requires a run through Stratholme to Baron Rivendare in 45 minutes - and depending on where that timer starts, that could prove to be a challenge. What are your opinions on this new armor set? Going to rush to get it or couldn't care less?
For information on the sets, PartingVisions has some nice images of the new sets as well as some information on individual pieces, and this thread in the test realm forum is attempting to compile known information about the Dungeon 2 sets.