just a note to our spirit shaman i am probably going to end with a pair of levels of Frenzied Beserker so you may want to make sure you eventually have calm emotions as a spell known. i dont know for sure yet but its something that may happen.
(Spirit shamans can change their spells known every day, so this is not a big thing to worry about just yet.)
And as for Frenzied Berserker, frenzy is ended with a DC 20 will save or until time runs out. Frenzied Berserkers somewhat scare me from the description, so please be aware that some people may not wish to fully buff or support your character. For example, a flying Frenzied Berserker or a Freedom of Movement Frenzied Berserker is out of the question because... Grease (Bard 1) or Ice Slick (Cleric 1) are maybe the simplest and most effective ways to stop you from killing us all. (No dex-based skill checks, so the balance check is always failed.)
We'd have to invest in these spells though, which is a little sad.