I've read A LOT more posts about negative reactions to Oxypowder than any other oxygen cleanser.
I have read many good things about colosan, however some people prefer Homozon, Colozone, or Oxy-Cleanse. It just depends on your own body. In some forums people shared that using colosan helped to flatten their tummy. Probably the result of releasing toxins and poo :) Homozon has been tested, and used safely to treat disease and cleanse bowls for over 100 years. This is not to be confused with the copycat homozone, which people report as also a good thing.
As I said everyone is different, in my opinion Oxypowder is less safe than the other products, but those who do not react to it say it is a very powerful cleanser.