My sorcerer gets a lot of use out of grasping hand. It's extremely useful against spellcasters, and even Medium-size melee characters have trouble against it.
Ideally, I cast it on a mage in the enemy back row. Assuming I penetrate SR, he's almost certainly grappled. There are very few damage spells with only V components, so unless he has both Still Spell and Eschew Materials, he's unlikely to be able to destroy the hand himself.
A fighter-type minion could probably rescue him by destroying the hand, but the minions will be in melee with my own allies. If a minion withdraws from combat to go attack the hand, he takes AoOs, and also gives my allies an opening to advance through the front line and gain tactical advantage.
Alternately, I can send the hand against a fighter-type in the first place. With its high Strength and size bonus, it's more than likely to win a grapple even against melee characters. Either I just keep him pinned for the whole combat, or my allies quickly hack him to death and I send the hand off to another target.
Special bonus feature: it gives me a legitimate in-character reason to yell. "Talk to the hand!" (Yes, I'm easily amused.)