I have an 80 Warrior and a 40 Guard and so far, the Guard will just not die. The Warrior is not as sturdy. That said, the Warrior has more interesting combat options (in my opinion). With the Guard I feel like I just default to Greatsword and Scepter/Shield for kiting.
Ultimately, I like them both. If you never want to die, you can do that with a Guard. If you want as many ways to chop mobs up as you can think of, you can do that with a Warr.