I switch armors like I switch weapons; All depending on the group I'm with, and the mob I'm facing. Guardian is my main.
I just hit 80 today on my Warrior. I've only geared him up half way, still playing with traits. DPS is definitely higher. Survivability is a bit lower, but not by much, since I've gotten really good about dodging while leveling him.
Playing my Guardian, I keep my party up while they do the major DPS.
This allows me to play my warrior with the mentality that my group's Guardian, is going to do the best he can to keep me up while I do my High DPS thing.
Guardians bring a lot of survivability to the group.
Warriors bring a lot of DPS to the group.
These classes have pretty strong synergy between them.
Definitely make one of both. They're very useful in dungeons, and it really feels nice to have a variety.
Structured PvP (sPvP) is essentially just your average hot join PvP.
Tournament PvP (tPvP) is 5v5, Knock out rounds, reward based PvP