only that they are crazy strong ...

the mid classes i would advise a beginner to play in descending order:

bonedancer (pocket healer and insta life drain. nuff said )
valkyrie (placing the valk here because she has heals)
thane (you can use DD-nukes and AoE spells to weaken the enemies)
savage (good dmg and survivability nice positionals and skillchains)
berserker ( hamster mode)
.
shadowblade (because of the extremely weak beginning till you get your most needed skills. high lvl is pretty fun though because of 2h PA )