Pros: Helps baby to latch on better
Cons: may decrease milk supply
I had to get one of these when my 3rd baby was nursing because I made too much milk and he used to choke every time he nursed. It was great because I was sore and with the nipple shield, I could barely feel him nursing. So not only did I have no pain, it also helped to decrease my milk down to where it should be. It also helped the milk to come out slower so that he didn't choke as much. But be careful because if you don't make extra milk then you might stop making enough to feed your baby!
I haven't tried any other shields to compare it to, but I feel that it's a great value and if you have a problem that requires this, it's great. Just always talk to a lactation consultant before you spend your money because it might not be the answer to you problem and may actually cause more problems in the long run.