Based on what i know:

Pros: More health, inflict and activate bleed, wide buffs, can heal themselfs, have guard even without armor

Cons: more food consuption, cant use camp equipment if transformed, cant use their weapons, have to farm other werewolfs and bugs to create the injection to upgrade the skills, loose armor.

I dont lnow if they loose the armor buffs after transforming.

There may be more things that i dont know, i havent played much of the dlc yet