For the 3 dragonshards I burned getting it, -36 HP and -2 attack (dropped weapon focus, toughness x 2, and dwarven axe attack 2), I'm not convinced. While the AC bonus is bugged in our favor, I think I'll keep it. But after they fix it... I'm undecided.
About the only benefit is that Spring Attack lets me move to break the swing animation (preventing the dreaded 5th attack) without a penalty.