I know why they are asking this, of course. Once upon a time, I made the HUGE mistake of brushing my parents' cat, Caymus, with the Furminator and completely ruined the LOOK of his coat.
Yes, that's right. I didn't ruin his coat - but I ruined the look of it. Why? The Furminator has razor blades that cut the fur and remove even the healthy hair - so you are left with a dull looking coat. It does the job of getting rid of fur, but it does more than you want it to.
That's why I like a brush like the Equigroomer - it does not cut the fur - rather, it pulls out the dead stuff. And an extra bonus is that my Ragdoll cats, Charlie and Trigg, who hate to be groomed will tolerate the Equigroomer pretty long - like 5-10 minutes vs. 5-10 seconds with other combs or brushes.