The pros. are that it is easy, painfree, non-surgical and no risk involved.
There really isn't any con! The only minor thing would be that you have to wear a Spanx one piece, but really you get use to it fast and its fine.
I did the Zerona as I wanted to get rid of fat in places that it is not easy to do so unless you want lipo. If you drink lots of water and exercise moderately, the proceedure works even better.