As written, Wolfbrother is a pretty weak prestige class.
BAB and saves as a cleric.
2 skills per level
d8 HD
Class abilities are meh: talking to wolves telepathically, calling wolves to aid you, scent, track by scent, low light vision, skill bonuses, +2 constitution.
Plus there are WoT specific abilities: wolfbrother gets +5 defense in 10 levels and +3 reputation, he is able to enter Tel'aran'rhiod. I don't know how powerful that is.
Anyway. Almost any class/prestige class is better than wolfbrother, i.e., the later you enter the class, the more powerful you can be.