Mana spring is a nice totem, especially now that it can be stacked. BUT..
There's is one major weirdness about it - it scales inversely, meaning it becomes worse and worse as your gear improves. Why? Because of the change to mana cost for spells that Blizzard introduced in 3.0, where most/all spells use a percentage of your mana pool. Combine this mechanic with a fixed mana regen tick on the manaspring totems, and you are experiencing inverse scaling, meaning your can get into mana issues if you increase your intellect.
Not very likely due to our mp5 talent in elemental, but still... it's -very- strange to me that by adding intellect to our gear, we might run out of mana easier.
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