Its a bit of a mixed bag - not too bad for non-glorantha, with some intereseting ideas, though its a struggle to get full use in the gloranthan setting.
Some of the spells can seem pretty pointless, like Cadaver eternal (other than for funeral rites) but they can be adapted to other uses - like players using it to keep meat fresh while at sea.
I've only really integrated the rune spells into the campaign as the spread of spells per rune is pretty thin on the ground. The biggest niggle with the rune spells is the rune requirements feel inconsistent or contrived. I've ended up including new Runes (lightning, disease, Unequal Exchange to name a few) to compensate and change some of the runic requirements.
Also ended up adding Rune Strength (in line with the rules from Gms Guide) requirements for certain spells to restrict their ownership.
I've not really used the Sorcery or Divine magic from the book in a live game, but seem a wee bit unbalanced.