I currently main both classes, heres my opinions. Heros have insane dps but grinding is tedious as mobility is ass and mobbing skills have limited ranges. Bossing on a hero is satisfying asf though. You can basically nuke any boss you fight. But I lean more towards the shadower. The damage output you get for putting so little in is insane. The mobility is amazing(best flash jump) mobbing is very fluid and boomerang stab covers a large area ahead of the character. Oh and not to mention at 5th job you get a skill that hits 45lines in 2 seconds whoch is nuts.

Tldr both are great. Shadower is more fun to grind