This is, overall, a great cat litter. I'm all about natural foods and all, but I'm a bit less worried about using sub-par (health-wise) cat litter. I feel that if you clean the littler box well and often, your cats won't be breathing in litter fragrance all day long - they're in and out in 30 seconds to a minute. My cats never had a problem with Fresh Step litter - it clumps very well, so as long as you take care of that at least once a day, it'll be clean and smelling very nice.
I have two cats, so this multiple cat formula is perfect. I'm really not sure what the difference is between this...