It goes through all magic immunities, it freezes even buildings (including your own) so towers don't shoot. Chrono doesn't affect only FV and units he contrrols, so if rubbick steals it, it still stuns everybody, even him, except FV, so it's not that good spell to steal. That is why you sometimes see FV with Necronomicon, the minions can murder the poor guy inside the sphere. The only other unit unaffected by it are couriers.
I think Shadow Shaman is my new rating-whoring hero, so much power all game long and solo kills towers on top.