It is a copper based product that requires you run at least a .5ppm FC so there is residual sanitizer. You would have to use it in addition to chlorine!
for the pros and cons of it read Ben's FAQ on metals here:

http://www.poolforum.com/pf2/showthread.php?t=98

My own feeling is that copper is going to cause problems and it is not as effective sanitizer as chlorine. I really don't want to take a chance with the health of my family. Do you?