Please help me decide a class

I have warrior, guardian, and mesmer at 80. I enjoy all 3 and have a basic understanding of them, but I'm only interested in pvp and wvw. I've just returned from a couple years away and trying to decide what class to really focus on and get good with.

I'm not concerned with what's meta or op, just whats a good one to start learning pvp and wvw with.

Guardians and Mesmers are probably the two classes with the best "dominance" in the meta (are usefull and powerfull in each department of the game), with multiple viable builds. The main differences are that Mesmers will always have the upper hand in duels and 1 vs 1 and small scale fights due they have access to stealth, insane burst and better mobility and disengaging tools (also, confussion is a nasty condition to deal with). Guardians are like a pillar in the community, Mesmers more like a full time gankers (they provide mandatory buffs, but are more known for how annoying playing against them is).

if you have pof, try spellbreaker, war's espec

I do have both expansions. Thanks for the suggestions.

If i go guardian what elite spec would you guys recommend?

firebrand if you want to zerg in wvw, dh/core for solo roam

Go with mirage probably the strongest class in game +you will never nerf hard