ZB > Bloom for sure.
ZB takes more skill then bloom as well, i really hope they have ZB in halo 4, even though bloom wasn't a bad idea, it wasn't implemented correctly.
Fixed.
Also, i find the halo reach system is better as it gives you more of a chance to survive in halo, unlike in halo 3, where if you had low shields you were ****** regardless, health is good.