My husband is a CAT mechanic that works with heavy machinery and generators, he's contantly testing electrical current. He coudn't wear his metal ring at all, it was just too dangerous. These have been a great alternative, he wears one everyday. He's very rough on them, but they are pretty well made and last quite a while. I'm not going to say they look expensive or as nice as a traditional wedding ring... they don't, but they serve a purpose and are a great alternative. He has several in different colors and wears them at work and switches out to metal on the weekend.
Cons: They do seem to stretch overtime and usually have to be replaced or they end up sliding off wet hands.