I have several bars at home. It is an excellent tool for the laundry arsenal.
In this thread I've seen the problems with using at a professional carpet cleaning tool.
1. It doesn't rinse very well. Sure, stain(filtration line) is gone, looks great, but it is nothing less than a lengthy and water intensive process to remove all the soil attractive residue. When used in laundry cleaning you have the benefit of an agitated soak and a long agitated soak rinse. The disadvantages of using a product containing a true soap with HWE is something I guess people just have to learn all over again.
2. When you look like an amateur, you are one.