They (hopefully) have similar outcomes, through very different processes.
Check out the Andreas link above for interseting info on Oxy stuff, or look at hanna's posts just a few threads down. I just posted about Colonix... check a few threads down on the 'colonix or P&B ' thread, and also be sure to read the bowel cleansing info from the Dr. Schulze (link above) and the cleansing link above.
With a little research, you will be able to discern which one will work best for your issues / body type.
Congrats! You are about to start an amazing journey! Best of luck!