Help decide between guardian and necromancer.

Hi,i like 2 class guardian and necro.Which one between this 2 worth to main?I want for: Fractals,farming,WvW and story.I know all class there are good but i want to invest time in 1 .Ty

Guardian is a far better class for fractals (both as condi firebrand and as power dragonhunter) and WvW (support firebrand, power guardians). There are no instances people ask for necromancer in fractals, despite many players playing reaper. Any content without the protection boon on enemies can be easily managed either on power Dragonhunter or condi firebrand ; even harder bosses that burn can be done with trailblazer or dire variants of condition firebrand (due to Balthazar rune and smoldering sigil providing burn duration). Protection only really affects power damage so condi firebrand can work around it.

A common misconception is that power reaper has high quickness uptime, when in actuality you can achieve 100% uptime on firebrands (power or condi alike) with merely ~25% boon duration , which is trivial with fractal potions. In order to achieve any form of quickness outside of reaper shroud you need boon duration on reaper and outside of shroud unless you run curses traitline your critical hit chance will suffer immensely (compared to running soul reaping which has a 10% damage bonus and 33% crit chance bonus in shroud).

Necromancer is only better for solo content as scourge when melee range is nonviable, particularly when you can abuse epidemic. Against comped teams in WvW the current mobility meta with scrapper is extremely unfavorable to scourges and reapers. You will be deprived of life force due to the longer fights compared to before February 2020 and any boon corrupts carry far less value than a boon rip.

For fractals refer to https://discretize.eu/builds

For WvW refer to https://gw2mists.com/builds and https://metabattle.com/wiki/WvW

edit: as far as farming goes, refer to https://fast.farming-community.eu/farming/builds/guardian versus https://fast.farming-community.eu/farming/builds/necromancer

for Fractals & farming, Guardian. I started out as a necro, but now mostly play Firebrand. In T4 and higher fractals, Heal Firebrand are requested a lot. farming out in the open world, I love the fact my HFB (Heal firebrand- aka healbrand ) with shield block attacks from Mobs....XD.. highly recommend Guard- Firebrand especially..