My preference is for Fresh Step. It seems to control the odor the best.
You might also rethink your cat's diet to help eliminate some of the odors. On the recommendation of my vet, I feed my cats Hill's Science Diet catfood, not for special dietary needs but for a noticeable difference in litter box odor. I buy it at my vet's office or from the local Petco. It does cost a little more, but the extra cost is worth it to me.