Yes Jimmy, it cleans better than the liquid acid rinses.
I don't know that every cleaner really needs to use it. There isn't an overwhelming need to "neutralize" every carpet we clean. I'd much rather a cleaner leave a very small amount of alkaline cleaner in a carpet than too much of an acid one.
The goal is for as little residue as possible, not a specific pH level, unless we are talking upholstery with very sensitive dyes or things that might brown. I was in a meeting with the biggest producer of nylon carpet at the time, and he wouldn't be pinned down to a pH level on carpet after cleaning. He was more concerned with surfactant residue, because that is what caused resoiling, not pH alone.
With the increasing popularity of polyester, issues of pH and neutralization may not be as important as they once were either.
In the end, its another way to get things clean for cleaners who prefer very high pH prespray products, or who like an "all in one" carpet and upholstery cleaner in their extraction machine.
If I just want to use an acid rinse to rinse, and not to clean, I'd stay with a liquid product; they are about half the price of Flex Ice, unless my math is wrong. But since its a cleaner too, that's not the comparison I'd make.