Hi! i need an advice, i decided to roll a troll mage alt to get him through new cataclysm content and i want to buy one heirloom item (with champion's seal currency), staff or robe. I dont want to spend any justice points, i want to save them up for cata (i will have 3k-4k when new expansion comes) so i want to buy blue items (one or two) when i hit 85lv. My question is, which heirloom should i buy - robe with 10% more exp or staff with spell power. Thanks for help, cheers!