Well I personally don't own this product but I have used it before. I wanted to look as stupid as possible so I put one of these on on the outside of my clothing. My friend and I both had these on when doing a suicide run and we really didn't care about getting hit we just wanted to look as dumb as possible even though we already did running down the hyperball field screaming. Anyway yes these do exactly what they advertise. They protect. I got wacked twice in the chest and these worked perfectly. HOW COULDN'T THEY WORK!
ummm well they don't have anything bad about them except they don't bounce ANYTHING. But really they aren't made to bounce anything just protect so really there isn't anything bad.
I personally wouldn't wear one for actually everday play. I really wouldn't recommend them to anyone except for those who don't care how stupid they look. I would recommend them to a field though because you'll sometimes have some people like little kids or moms that will want one. So if you want a chest protector then this one works perfectly.
You can wear these under some baggy cammies, and they work pretty well...extra airspace under your shirt, and some protection. The best thing about them was when I fell on a rock and it didn't even hurt!
I would recommend this. Not at comfortable as those flexible protectors, but feels like it protects more. No bounce, though.