Guild Wars 2

well that depends on what you are looking for out of your heavy both are amazing classes but can specialize in different things. Do you like super hard hitting burst damage? DPS warrior. Do you like being a powerful support and healing tank? AH Guardian. Of course you can spec both classes differently than what I mentioned, and flip the roles, but each has their up and down sides. My advice would not ask someone which class to make, but to look them up for yourself and decide based off what you found/what you find interesting.

they are both pretty good, seeing as how we are in the warrior section i have to go with warrior however.

in pve they are lots of fun, you can roll entire waves of enemies, almost always loved and often considered essential in dungeons. great access to offensive boons and lots of build variety.

for WvW however i would have to go with guardian every time. even though warriors are fantastically mobile and hit insanely hard in WvW guardians are better because of all of the sustain they possess and combat tricks they can do.

if you want a frustrating time in WvW with bright shining moments of victory then go with warrior, if you want a nice relaxing time with clear ways to help your group then go with guardian.