I use that myself, usually with the help of a seasoned sponge or something but not always. I've had great luck with it. I don't continue to use it though like the directions tell you to, just until the tank is cycled. Sometimes if my parameters are a little off and a w/c doesn't help I'll use it again after a w/c. What's funny is the person who recommended it to me doesn't really seem to like it and doesn't have much luck with it.
I have to wonder if these products are something like the stuff that Tetra recommends, Easy Balance with Nitraban. Because both the Easy Balance and the Special Blend say (not that I would) they reduce the need for frequent water changes, etc. Never had the inclination to compare ingredients.
55 gal with 3 fancy goldfish. 2 goldies in QT, 23 flatback hex tank with betta, 3 ADF's, 2 BN's and nerite snails, 60 gal community tank: 4 angels, rainbow shark, raphael cat, apple snails,etc.