Well, hard to tell what you will like best. But my rundown on them:
Warlock: too easy, have instant dmg up or be useless. No in my opinion.
Zerker: Great dmg, good group utility, will have a harder time vs high stealthers. A good option.
Skald: Decent dmg, great util, groups should use one, and its good to solo / duo. Another good option.
Sb: With their boost, they become good again (this is with 1.82 D, not sure when that hits europe) When that hits, assassins will get balanced again, brittle guards wont have to stop you, so great for solo'ing. But obviously no groupability. So a good option with 1.82, but if you want grouping and only one main, look elsewhere.